In addition to the excellent answer provided by DG Gage, I think I see the issue in your current setup. If you take a look at your debugscreenshotone.png, you’ll notice that the Object input on your Cast To MyCharacter node has been left unhooked. With this unhooked, the blueprint simply doesn’t know what you’d like to perform the cast on. To fix this, drag off of a Get Pawn Owner node and connect it to the Object input of your Cast node. This will basically say, “get whatever pawn owns this anim blueprint and cast it to MyCharacter.” I believe that should get you crouching ASAP.
Good luck.