Replacing a power window motor is not fun because you have to remove the inner door panel. Some door panels just pry loose from the doorframe, but many require special tools to release the clips that hold the panel in place. The best advice is to look up the door panel removal procedure in the OEM service literature so you can remove the door panel without damaging anything.
If the fuse is okay, there may be a break in the wiring that routes power to the power window motors and switches. You�ll probably need to look up a wiring harness diagram for your vehicle to identify and trace the wires in the circuit.
It is not likely that a fuse or relay will cause a single window to not roll up or down. More likely, the power window motor, door switch or window regulator has failed. Looking for symptoms helps guide us to the most likely cause.
Checking the power window motor requires us to remove the door panel. Each vehicle has a unique attachment method, but carefully prying the panel from the door removes most.