Several gangs are locked in a turf war, so you'll have to choose a gang to work for then take jobs from them by answering their payphones. All of the jobs require speed, and since walking is getting you nowhere fast, you will have to 'borrow' some transportation. Luckily, every vehicle in the game can be stolen. You must always keep an eye out for the police, though, or your game will be over in GRAND THEFT AUTO 2.