This guide will let you know how to do a Truck Robbery for Lester in GTA 5. You will need to follow the step-by-step instructions to do so.
There are two different locations for this mission, so you first need to go to the port side indicated as H on your mini-map. You have to steal a truck from there by going inside the garage, as shown in the image below.
If you steal the truck, you will see that police will rush at you, so you must clear your wanted level. To clear your wanted level, you need to go to the railways and drive on them because the police are not allowed to go there, and after some time, you will clear your wanted level.
After that, you need to drop the car off under the bridge, where Lester will tell you to complete your mission.
Now you will receive another phone call from Lester, and he will ask you to steal another truck for him. You need to open your minimap and go to the highway where the H is on your map. When you get there, you will find a truck, so you need to block the road first, and when the truck stops, you need to steal it and drop it off at the garment factory, as shown in the image below.
You also need to make sure to lose the cops before going to the factory, and when you get there, you need to park the car and exit it to complete your mission.