Amazfit Watch faces

I have the AMAZFIT GTR 2e and would like to install some more watch faces than is available on the Zepp app,
There is an app on Google Play Store called "Watch Faces & Amazfit" that claims to work with ALL AMAZFIT watches from the BIP to the GTR 2. It says all you do is pick the watch face and tap ...

I think while watching a Youtube video about the GTR 2e, Someone said that the screen timeout can be set to as much as 30 seconds.
Can someone tell me where on the watch I can do this?