Hi Joseph.
There are a few ways to do what you need.
The quick way is probably to weight paint (subtract) the weights from that group.
However you can remove all the verts from a group in the Vertex group tab.
Select you verts, then highlight the group in that tab, then hit the remove button.

I can’t annotate with this snipping tool but hopefully you see it right next to the “assign” button.
I have a feeling that you haven’t taken the fundamentals course before tackling this one though.
Am I right!?
I even waited for you to finish, right at the start of the course. haha