It’s fairly easy (I have a library of myself doing about 140 different exercises). You go to workout builder, on the right side of the page about 1/4 down the page you will see “add custom exercise”. Click on that. A pop-up will open (make sure you don’t have a blocker on your computer). You will have a choice of downloading your own video by clicking “browse” (which I do from the IPAD that I am using to look at the site) or you can put the “youtube” URL on the right.