If you are familiar with the board you will see 9 (3×3) regions. In each region, you must place the numbers 0–9 in particular places.

The rules are these:

• In every row (full 9) you must have 0–9, with no repeats.
• In every column (full 9) you must have 0–9, with no repeats.
• In every region (3×3) you must have 0–9, no repeats.

Hopefully I conveyed it clearly :)

to win

When i play sudoku i like to use a pen and a pencil. I look at each square and figure out all the possible numbers that can go in said square and write them down in the the box. I do this for all boxes and then you can just look at it and start writing numbers in with pen in the boxes with only 1 possibility. Then you can figure out the next set of numbers and so on. I really don’t do this anymore as i can do the easy to medium ones all mental now but thats what i did in the start that got me good at them.