when I try to draw a line to create a walkable area, I get the message bow "You are currently using the eraser change the selected area number"
what/where is the the "selected area number" that I'm looking for. thank you.
There should be a dropdown menu on the right which reads "walkable area x". Change it to an area with non-zero number.
Walkable area 0 actually means the area that is not walkable, so if you draw with this "colour" it's actually erasing walkable areas.
This applies to other things like hotspots, regions and walkbehinds.