To restore the Radio Network in Radio Liberated in Far Cry 6 go into the building at the first outpost and pull the lever.
At the second location, climb up to the roof following the blue markings and then climb onto the security room on the side of the room at the top, jump down and pull the lever. Get out of the area by shooting the lock on the door.
Go around the outside of the room and look into the window on the other side to shoot the lock on the door. Go into the room and fix the electricity box.
At the third location, climb the rock to the west of the tower to the top and grapple up the radio tower. Climb up to the platform with the blue cloth. Continue to climb up to the next platform and then the vines to the top of the radio tower.