This guide is applicable for the following models:
X240, X270, X270PRO, X270 240Hz, X315PRO, C270, C315MAX
(You may find simplified version of this guideline in the physical copy of user manual as well.)
Take out the parts listed below from the packaging.
Secure the stand stem, and base with one screw.
Secure the shaft assembly to the stand stem with two screws.
Take out the panel from the packaging and lay it flat on the styrofoam with the back facing upwards. Then clamp the base assembly to the rotating shaft of the monitor and ensure there is a 'click' sound heard.