There is a NEW way to install WatchFaces! You can now install WatchFaces in the "Local Clock Faces" section in MiFit. There is also the possibility to choose the previous installation method (through the section "Online watch faces"). You can select it in the left menu of the application.
Required Android Versions : Lollipop [5.0–5.0.2] - Marshmallow [6.0 - 6.0.1] - Nougat [7.0 – 7.1.1] - Oreo [8.0-8.1]