Thanks for the tips! Will try those out

Quick questions, 
1) is there a way to "add more nodes" once a shape is already formed? Or would I need to start over with a new shape to do so 
2) How can I easily "carve out" a building or other feature in the middle of a parking lot that isn't parking. It would be great to be able to do the outline of a lot then cut out the building center of it 

Appreciate it