if you want to do it that way then @Marco_Ferreira himself is probably the only one who can tell you how he did it
Sadly . At this moment in time he is unavailable
Look for Clockskin Browser. It’s another program by @Marco_Ferreira. It allows you to test any WFD watchfaces you have in a particular folder. Like WFD, it does require JRTE, but if you are running WFD, you should already have it. It allows you to test on the Xseries graphics engine(finow and similar), King wear graphics engine(almost every other brand) as well as UL. If you have Clockskin Transfer, you can also set up Browser to upload faces directly. Note that CST is an Android app you download onto your watch. I believe that it creates a temporary ftp server that you can access on your computer or tablet. You can see what faces are on your watch and directly upload new ones or delete faces that you no longer want. This is especially helpful if your charging cable lacks data wires. Some companies did this to prevent installing bad firmware and upgrades that could corrupt and brick your watch. It’s also a lot quicker than transferring by Bluetooth. In any case, search for Clockskin Browser on this site. I use it all the time, as I currently don’t have a working smartwatch to test my faces on. I believe that he is currently on Ver. 0.10.2.