Let me preface this with “I'm not writing this for people to steal others work.” Currently you can download any unprotected WatchMaker file to use on your watch and customize it.
There is no feature that allows you to copy from one face to another. So without having to recreate the wheel, here is the steps you can use.
(You will be doing this on your computer, unless you want to install an app to open zip files on your phone)
Now you have the image(s) you need to finish your watchface.
Last step it would not hurt to reach out to the designer and thank him/her for their awesome work of art.