Replace truck fuses by locating the blown fuse, removing it, acquiring a replacement and placing the replacement into the blown fuse's slot. Keeping the malfunctioning system in mind, use your truck's manual to find the fuse that corresponds with that system. Some truck fuses can be removed with fingers alone, while other require tweezers or needle-nose pliers for removal.
All modern automotive fuses have two metal prongs that fit into slots on the vehicle's fuse panel. A thin metal wire inside the fuse's transparent plastic housing connects both of the prongs. After removing the fuse, inspect the wire inside the housing to see if it is broken. If the wire is still in one piece, then that fuse is working normally, and the problem is either in a different fuse or elsewhere in the vehicle. If the wire is broken, then that fuse requires replacement.
If you have a new truck, the manufacturer may have provided a few replacement fuses with the vehicle. For most used trucks, however, getting a replacement fuse requires a trip to the auto parts store. Take the blown fuse with you to the store to ensure you get a proper replacement. After getting the replacement, use your fingers to secure the new fuse into the slot.