Easy, put the brake cylinder and wavy spring washer roughly in place then take a ¾" AF ring spanner (used for removing the road springs and dampers) and place the ring behind the brake back-plate and over the slave cylinder spigot (and the wavy spring washer). Take a simple G clamp; one end on the cylinder, the other over the ¾" ring spanner, slowly tighten the G clamp until the wavy spring washer, compressed and flattened gently by the ¾" ring spanner, goes "click - click" into place.