Grohe Axor Uno Wall Mounted Single Handle Lav Set 38118XX1 Installation Instructions Manual page 5

Install the cartridge and anti-twist device in the
housing.
Install the cup washers and springs in the rough.
Install the cartridge assembly.
Installation with all models:
Push the handle over the cartridge stem. Tighten the
handle screw with a  mm Allen wrench.
If you are installing 38117XX1, turn to page 6.
If you are installing 38118XX1, turn to page 9.