1) Put the cutters back into the guards (Fig. 3)
2) Put the shaving heads back into the shaving unit. (Fig. 4)
Make sure the projections of the shaving guard (marked green in the picture) fit into the recesses in the shaving unit.
3) Put the retaining frame back into the shaving unit, push it down (1) and turn the wheel clockwise (2) (Fig. 5).
4) Check if the retaining frame is locked. (Fig. 6).
5) Put the shaving unit back onto the shaver.