My SOKIII have an alignment hole on the right side and all I do is insert a 3” cotter pin and slightly spread the end so it wind fall out. Fabric should have about 3/4” clearance on each end. I just rotate inward slightly till I can insert the pin. Then it’s locked to the spring. Then I remove topper and roller and move slide in 4 to 8 inches, hand roll topper on roller and reset into ends. 8” is close to one rotation of roller. That’s how I was told to put more tension to keep topper taught.