Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
@LEB-ID It's called Add new Server in XCP-ng Center too... old habits die hard. But Pools is not the right word either. It's hard coming up with something short and precise.
I can recommend gparted to resize your partions. It's easy and has a GUI. Important: you can't resize the boot partition without a live ISO.