Quote: "Can anyone help me figure out how to add nodes to the trigger zones?"
Trigger zones etc usually follow the contour of the terrain and do not cause that problem but with that being worked on it seems disabled for the moment.
Quote: "Also while we are at it, what are flags used for"
Flags are like waypoints for the character to follow .. You need to click the shooter icon to see the nodes and connect the logic as shown in the vid below
Quote: " is there a button to send the camera directly to the start marker?"
Not that im aware of .. Perhaps worth suggesting on a stream or Github
Quote: "but from high up does the build-able map look 5 km square- I can't tell. Last one, can you slide your editable area around on the map? "
Change the camera view ( top right ) use the slider to set your size and the yellow dot in the middle to move the editable area around.
The only person ever to get all his work done by "Friday" was Robinson Crusoe..