How to quit the Story Mode?

I just bought a PS3 Slim and GTA V. When I open GTA V, it automatically opens up in Story Mode. I don't want to play the role playing aspect of it, I just wanna play the regular version, like, the one where you steal cars, shoot guns, but not the story mode. Can someone help me quit the story mode please?

There is no "regular mode", the game only has story mode and GTA Online. You first need to play until the end of the prologue and the first mission. After that, you can go around the city freely and cause all the damage you want, but well, most YouTubers and Twitch streamers play on GTA Online, so that's probably what you're thinking. You can switch to GTA Online through the pause menu, on the online tab (after completing the prologue), or by holding Left-Alt (keyboard) or down on the directional pad (controller), and navigating to the bottom of the circle.