This is the first real mission in the game, now that you have learned the basics. Andreas wants you to pay a visit to Councilman Peralta so as to give him a bribe. Get in your car and follow the waypoints until you reach Peralta's villa.
This will be your first real opportunity out on the open road. If you get spotted by the police, perhaps for driving too wildly, be sure to lose them as you cannot carry on your mission until you are in the clear. Check out the Police section of this guide for more info on how to ditch the cops.
Once at the villa a simple exchange will take place and you will complete the mission without a shot being fired.
Reward: 100R$
Once you've completed this mission, feel free to explore some more or, head back to Andreas' yacht for the next mission.