Topping up the organic material?
Probably a silly question, but how do you top up the organic material without burying the worms? I would assume the worms need to stay at the very top of the materials right? Should I first remove the worms and vermicompost?
You can just add bedding. The worms will move up through the bedding to get to fresh food, after they finish the other stuff. The worms won't suffocate or suffer any issues being buried under loose, aerated bedding.
Yes. That's absolutely correct.