Hit alt+f11 to activate the VBA editor. You then need to hunt for the right
module where your macro is. Hit ctrl+r to get to a list of modules. This is a
treeview so poke around until you find your macro. Once you do it, you use
standard text editing keystrokes. The only thing that fails with NVDA is
detecting code completion. I have been meaning to file an issue about this.
The VBA editor is similar to the visual basic 6 editor in visual studio
vversion 6 I think.