Assuming you have the necessary hardware, as you noted in your question (that’s ⅔ of what you need) and as @Nullo responded (the missing piece you forgot to mention).
Assuming you have that, then you can follow your router’s instructions (now I see that you never actually specified that you have a “wireless” router, so I’m assuming that) and set the thing up so that you can connect to it via your wireless card.
You’ll probably want to set up some kind of minimal security, which the instructions can also tell you how to do.
If you don’t have the instructions for your router, you can generally look them up online with no trouble, as long as you know the brand and model.