How to restore a iPhone 4s? With just the buttons?

OK, so i quickly put a passcode on my phone because my brother kept taking it then forgot it and now I wanna do the restore thing but I can't remember! It was something to do with the home button and power button but i can't find it on google? Please help? Thanks so much!

Added (1). Lol, i swear to god i didn't steal it. You obviously accuse me of that b/c your the type of person to do that so.SHAME ON YOU. Thanks for nothing.

Added (2). Moe.

I meant the power button and home button.

You can't with out a reset from itunes, your gonn have to plug in the phone you stole and reset it to factory settings. Usally when a person makes a long excuse why they did this or that it's a lie admit it you stole it and you wanna be nibby

IPhone does not have buttons. It has a touch screen.