I only know the basic stuff too so I can’t really help much except to play the game with your teammates and see if you can get any better. Trouble is that you have nearly no time to practice. Just do the best you can is all I can say. I always take forever to move and I know in tournaments speed is a factor. I try to overthink several moves ahead and I can’t go fast.

This may sound negative but I would try to set myself up mentally for failure since you know the deck is stacked against you. Just be sure you don’t let it affect your self-esteem. I would try to pysche myself up by saying “I know this is not a great situation. I’ll do the best I can and if I go down in flames, that’s ok.”

But I understand your frustration.

Think perhaps your opponet is going through the same feeling as you, and maybe just knowing that may give you hope that you do have a fighting chance.

Consider that your “because my school has no one else” that makes you a brave person to step up regardless of the outcome, as you are fighting against all odds, and don’t be surprised if YOU DO WIN IT!
Winners aren’t born rather they are MADE from circumstances that bring out the best in a person. I wish you the Best outcome, Flutherrites are here to cheer you on!

A week is as you realize, a tall order. Your best hope is that you will be matched initially with a novice on the level of yourself. But remember the basics. Your objective at the opening is to deploy your pawns and minor pieces with the objective of controlling the center of the board. Arrange your pawns such that they support one another, while offering your bishops freedom of range and restricting the options of your opponent’s bishops if possible. Early on it is the pawns knights and bishops you rely on to arrange the battlefield to your advantage. Keep your heavy weapons (rooks and queen) in the garage until the board is cleared of the debris inhibiting their firepower. Pulling them out too early will allow your opponent to develop ahead of you through simply threatening your major pieces while you waste time and moves in their defense. In the week to come, I suggest you familiarise yourself with at least the old line classic openings. If you are white, play it safe by opening with the center pawns. I would also strongly recommend and not just for this tournament that you make a habit of playing against those whose level of play exceeds your own. And I cannot think of a more certain route to improving your skills on your own than acquiring the habit of solving chess problems. For my money, no one to this date can match the wonderful collection of Sam Loyd whose books remain the bible on the subject. Set up the board and figure them out. They will train you to analyze positions and you are guaranteed to steadily improve. Good luck.

A basic strategic principle is to control the center—not to the point you’re throwing away pieces, but if you have a few options for your next move and one option allows for that piece to take pieces in the center, then it’s more likely the better move.

Look for opportunities for your knights to fork an opponent. That means your knight can attack 2 different pieces at once, but they have to choose which one they move to safety and which one to possibly be captured. You’ll need to learn chess notation, which is really straightforward, so you can understand the moves that are in books and websites. Just get your board out and follow the moves along on your set.

You can do a lot in a week. I agree with @HP‘s suggestion of reading some basic chess openings (also learn the fool’s mate and the scholar’s mate so you don’t look silly right off the bat). I have to think there are probably tools for learning chess strategy that are freely available online. Things like chess puzzles.

At the end of the day, just have fun with it. Chess is an amazing game and I think it’s pretty cool of you to step up to a pretty big challenge. You may surprise yourself, and at the very least, charging headfirst into certain defeat can build character. Also feel free to post questions if they come up for you.

You could find a good chess program (or “app”), and play against it a lot. Start at the lowest level and play many games, increasing the difficulty when/if the one you’re on seems unchallenging.

Tell your parents it’s for school, and you can play the game for hours as preparation for this extracurricular activity.

The only thing I have to add to the good advice already given is to make sure you understand the special moves of castling and en passant.

I knew how to play chess when I was 18. A 8 year old boy from across the street came over to the house one day and wanted to know if I wanted to play, I said yes. He beat me in less than 8 moves. Never played with him again.
If you are going to play chess, know how to play! Know your opening moves and such. Or stay home.

Just learn the tricks like:
En passant

I did my first earthquake move in grade 9. I flipped the board and threw the pieces everywhere. I still won the tournament, but I really should have gotten into trouble after that.

I also mistook En passant for being able to kill the opposing player’s queen with a pawn. I should have gotten into trouble for that move too.

Don’t forget to castling when necessary, that’s about all I know. https://en.wikipedia.org/wiki/Castling

I found this site to help improve your play for novices and there are several others that have free games for you to practice playing. I remember my son competing in a science competition when he was in grade school. It was his first time and he said his other team members were better prepared and had lost in the past. In the history of the school, they have never won a competition. It was an American school in Japan against better-funded private schools. He thought for sure he wouldn’t even place in the top 3. Team wise they did not but in the individual round, he came in 3rd. The school made such a big deal of his win because they finally won. His teacher didn’t expect it, and neither did he, his teammates nor the other competitors.

He was so nervous and thought he would be slaughtered and I told him to just do his best and have fun. So try to learn some moves and do your best and remember to have fun. It’s not the end of the world if you don’t win. It’s a game. Even when I lose a game I often enjoy other people’s skills because it teaches me where I went wrong and how I can improve.

This won’t help you for this tournament, but for future reference, recruit some players! There’s only 3 on the chess team in your school?

You have a week so you can learn some basic openings like the Queen’s gambit. That will help you understand that some players use these patterns like a crutch and if you see what they’re doing you can use it to your advantage. If I only had a week I would be drilling chess puzzles. They’ll teach you how to recognize certain things that won’t come intuitively for a beginner. Chess.com has some free puzzles. I would find an app or chess solitaire game that sets up these puzzles for you to solve and just do a lot of them them.

There’s lots of resources on YouTube. You can find beginner tutorials.

You don’t need to learn any openings, but you can learn some basic principles. Pawns compete for the centre. Develop your pieces early. Castle early and keep the king safe. Don’t put your queen in positions where it can be attacked. Try to avoid doubled and isolated pawns. Avoid moves that lose tempo (where they do nothing or where a piece is forced to retreat).

You can follow basic positional guidelines: Knights are stronger in the centre. Pawns are stronger in a chain protecting each other. Rooks like open files. Try to put pressure on weak points of your opponent, like a piece that hasn’t much protection from other pieces.

Certain exchanges can be advantageous. Bishop pairs are typically slightly better than bishop/knight and knight/knight.

You can learn basic tactical tricks: forking, skewering and pinning.

Most important of all: make sure to not leave a piece hanging (undefended) whereby your oppoent will simply take it.

Hey, how’d it go? You never told us! I hope you had fun and that it was a good experience overall.