Edit Terrain Editor

Help!

I have looked all over for tips to return to the Terrain Editor once my map is rendered and have been unable to find anything.

I have created a rough draft of my map in the Terrain Editor and went to render it only to dislike the outcome. I have been trying for hours to go BACK to the Terrain Editor and edit my map on a macro level.

Additionally as another troubleshooting issue, I put the player locations (6) on a Max 8 player setting and it fails to render; the whole render is blank and the error codes require a starting position for each 8.

Instead of starting from scratch in the Content Editor startup, how would one return to the Terrain Editor paint/tile screen prior to rendering?

This would be silly if each time one would have to start from scratch.