That’s really easy :
Hold the fixing system with your hand as shown on the picture. This way, you will have much more support to fix your Applixx;
A bit of logic is needed as when, kids, we were trying to put cube through a smaller circle. Present the Applixx close to the fixing system as shown the picture so that there is a geometric correspondence;
Reverse the Applixx onto the fixing system so that the latter gets into the Applixx;
Eventually, turn the Applixx by 90° in the direction you prefer until the Applixx is blocked.
You are ready!