you need to loosen the 2 mounting bolts and 1 nut and then start threading in the M6x1mm bolt slowly. You need to give some time to allow the hydraulic fluid to flow. Failing to loosen all 3 mounting bolts / nut and threading in the M6x1mm bolt will result in a broken tensioner. You can still use the broken tensioner worst case, but it will be a bit of a pain to set correctly. It's basically the arm where you thread in the M6x1mm bolt to collapse it that breaks off.