Myleague Custom Jerseys to Custom Roster?

Is there a tutorial on how to transfer custom myleague jerseys/logos to a normal roster? I've been looking for a couple days and haven't been able to find anything. Let me know if you guys know a way. Appreciate y'all!

https://www.youtube.com/watch?v=D7qZmGobJ8M&t=1068s

There are timecodes here to navigate what you need. Big shoutout to TGsoGood. Great work.