Ich habe es inzwischen anders gelöst.
Ach so: Ich verwende das Ashe Theme.
So, I think I figured it out. The problem was that woocommerce and the extension created a whole bunch of pages for me and they were already in the menu by default – which I couldn’t access -, but to change that menu, all I had to do was create a new menu. That somehow made the old one disappear and allowed me to start over, creating my own custom menu.
Strange.
Thanks anyhow, Matthew!!