Los Santos is a big place, but you have a map at your disposal with most locations marked with icons. Open it with ESC and double click any point of the location you need directions to and you’ll get a route to follow right to it while in a vehicle. Not owning a vehicle yet, you can rent a free bicycle at any bike station, call a friend, ask on Twitter or a fellow citizen, call for a taxi (if there are active players working the job) or go one of the illegal routes and attempt to take a local’s car (Press F at the driver’s door to pull them out and get in).
You already have your Driver’s License, so when you have enough money saved, you can purchase a vehicle at the car dealership. If you’d like to be able to purchase a motorcycle, you’ll need to pass the exam and get a motorcycle license at the Driving School. All vehicles you own can be stored or found at any garage. If your car breaks down, you can take it to a mechanic or call for a tow by going into phone>favorites>mechanic> tag for tow. (this only works if there is an active mechanic) or use a toolkit from YouTool (it will only fix the engine, not body damage). You can also fully repair your car and customize it at Los Santos Customs (the spray can marker on the map). If your vehicle goes missing or is impounded by the police, check any impound lot. You can loan your vehicle to another player with the F2 menu and give them the keys if you purchase a keyring from any Green Store or YouTool. Keybinds for driving can be found on the overlay in the F2 menu.
You can purchase melee weapons at any AmmuNation or YouTool. If you wish to purchase guns, you’ll need to buy a firearms license from the Ammunation near the car dealership before they will sell you a gun. To aim your weapon, hold the right mouse button. To use your weapon or fist (no weapon equipped), click your left mouse button. Additional keybinds can be found on the overlay in the F2 menu.