Gymrex GR-MG 52 Manual De Instrucciones página 23

STEP II
a) Place the headrest (8) and the backrest (7) on the main frame. Place the seat
(14) on the machine support (6). Align the mounting hole axes. Lock the
structures from the bottom with M8x25 screws and M8 washers.
b) Insert the support (6) into the main frame opening axis. Lock with the
adjustment lock.