The installation is the new housing also very easy as there are but apparently were problems with the previous version, here again in detail:
The two spacers and side walls are unscrewed, the PI is bolted to the spacers and then inserted so that the terminals engage on the side wall (especially the jack). Since the new PI on the other side has no connections here tidy air and you can easily readjust to the threads of the spacer are consistent with those of the case. Now you have to use only the side walls, tighten all screws and finished.
Conclusion: Not my first, but definitely my last case for the Raspberry Pi. Strong buy recommendation!