At the beginning of the adventure, you'll have a series of simple missions to complete, like picking up your character's father's car, which is parked in a nearby parking lot, or going to find your childhood friend and bring him home. Other missions are scattered around the map, and you just need to get yourself in the vicinity of each to start them.
However, what really makes Crimelife 3 fun isn't so much completing the missions as it is wandering around the city doing what you please. Just like in Grand Theft Auto, you can explore all corners of the city... you can visit the beach, steal cars and motorcycles, buy pistols and machine guns, shoot at police, get in the middle of a gang war, etc.
Best of all, your protagonist has a grappling hook pistol like Rico Rodriguez in Just Cause, which you can use to hijack any car, even if it's moving.
Crimelife 3 is a fun GTA clone that, though it may not be as big or as good as San Andreas, still deserves a lot of credit. After all, Crimelife 3 was developed but just one man, and the result is truly spectacular.