I'm reading these instructions for iOS phones but thinking your phone needs to be jail broken in order to do this?
Installing the Watch faces via AmazTools (iOS):
Open the file and select the [Browse] tab at the bottom.
Select my Iphone in the [browse] tab and find the Amazfit folder
Find the watchSkin folder in the Amazfit folder. If there are files in it, delete them all first.
Open Amazfit, select a dial to synchronize, and then enter the watchSkin folder after synchronization, A new folder will appear. This is the dial file you just synchronized. When you enter this folder, there will be a dial file (*. bin) and a picture of the dial, and copy the name of the file. Delete this dial file later.
Copy the dial files you want to replace into the watchSkin folder, rename the copied dial files to the name of the official dial files you just copied, and, The dial picture doesn't care about it.
Return to Amazfit and synchronize the dial that was synchronized just now
Or use AmazTools: