miriam, on the White, it may like my 1970s MW. I had to pry the top plate off using a very small knife to get started, then two screws appeared so I could take off the end cover. Still not a lot is access, but enough so I could remove the broken belt and put in a new one. I'm still looking for a very narrow belt for it. As you part out machines, I need a bobbin case for that one - right now, it has borrowed the Admiral's, and maybe a foot pedal for the Admiral.
The tricky part with these old ZZs without a manual is knowing the right combination of the knobs and levers to get the stitches you want.
QwerkyQwiltz, welcome. You are in the right place. If you go to the vintage machine forum, you'll find threads on 'Pictures of vintage machines', 'Pictures of quilts made with vintage machines' and several tutorials on cleaning machines and cabinets. I like your avatar.