This seemed like it should be easy (which it is I suppose), but it took a little searching to find the easy answer. I come from AutoCAD (a long time ago), so the plane that you were working in was called the UCS (the User Coordinate System). Changing the UCS in AutoCAD was pretty easy, you just typed ‘ucs’, and it would give you the options to select an object, use 3 points to define it, etc… It took a few google searches, like “Blender set the plane”, “Blender set the UCS”, and “blender change coordinate system orientation.”. Eventually found some answers, so to change the plane you’re working on in Blender:
1. Select an object that has an edge lined up with the coordinate system you would like to place.
2. Switch to edit mode
3. Switch to ‘edge select’
4. Select the edge that is in line with the desired coordinate system
5. Go up to the ‘Transform Orientations’ dropdown
6. Click the ‘+’ icon to add a new one based on the edge selected