Locate the release lever on the right side and turn it clockwise. When the lever is pointing up, the roller is locked in place. When the lever is pointing toward you, the roller bar is raised and the rollers are ready to be adjusted.
Grasp the roller body and roller head and twist into the unlocked position.
Slide the roller to the desired position and twist to lock in place. Once you have your roller adjusted, return the release lever to the upright position to lock it in place.