Need help with Joy2Key software

Download xpadder it is a much better program you can map any keyboard key to the 360 buttons and even use the analogue stick to control the mouse pointer and much more.

 

In order to use joy2key, you have to know which buttons correspond to your controller, so that you can assign any key to it.
Assuming you run windows,the easiest way for me to do this, is opening Start>control panel>Game controllers, then you select your 360 controller and press proprieties. This way you can test each button and see how are they mapped on it.
You will open at the same time joy2key, and assign the desired keys.
For my PS2 controller for example the buttons 1, 2, 3, 4 are the triangle to square, and 13, 14, 15, 16 are up, right, down, left.
I don't think the analogic works.
If you have any more specific question feel free to ask.