The installation method for GTS is the same as the GTR method:
1. Download the custom watch face *.bin.
2. Go to amazfit to synchronize an any official watch face.
3. Open the directory "/Android/data/com.huami.watch.hmwatchmanager/files/watch_skin_local"
and find the folder with the official watch face you just synced. After opening, there is a .bin file.
4. Copy the name of the bin, delete it, and then copy our custom watch face, rename it to the original name (name you just copy).
5. Enter Amazfit to find the same watch face you just synced and resynchronize once again.
Hope it's help