Does this help: https://www.hometalk.com/33636151/how-to-tie-a-bow-like-a-pro?expand_all_questions=1?
Here's some more.
Carol, I am not sure what a loop over bow is, but here are some tutorials on making bows. There are many more available by hometalkers, so if you want to look at more tutorials go to "explore projects" then "decorate" then I typed "bow" in the search box.
I think this will help. https://www.hometalk.com/33444408/how-to-tie-a-multi-loop-bow