In principle, after loosening the screw item 25 or the nut item 21, the blade can simply be removed from the cutting head and the new blade reinserted - it may be necessary to pull slightly on the pull sleeve so that the gear engages with the teeth of the blade again and can be fully inserted.
Alternatively, the housing can be opened to replace the blade by loosening the six screws (item 11) - please note that the turquoise cover (item 17) is under tension due to the spring 16; it is therefore best to secure it with one hand when opening - wear safety goggles if necessary as it may spring open.
Do NOT open the screws pos. 14 - these hold the spring mechanism in pos. 19