YOu are a COYOTE, a guide for those who wish to make their way into the United States undetected.
Use the mouse and left-click on a marker labeled GO to move there. Border Patrol guards will appear. If they find you, it's game over. If you elude them, you may continue.
Make your way to the big truck at the top of the map and make the handoff to earn points. You win when you earn 500.
You can also pick up more customers along the way, as well as supply caches to earn points.
The more deliveries you complete, and the more passengers you drop off, the more points you will earn.