Not sure exactly where you're hung up but maybe one of these is the answer you're looking for...
1. You can rotate your camera with the middle mouse button (or 'Q' and 'E' on the keyboard) to work on the back of the building you're working on.
2. You can "complete" that building by hitting "Done" and then starting a new building with a new grid.
Hopefully one of these is what you're looking for.
Thanks for your help, but it doesn't work.
The Q and E keys will let me move horizontal left and right, it wont rotate to see the back of a building that i am creating, i can only see the side that faces the main entrance.
Yeah, either use the middle "scroll wheel" button on your mouse to rotate the camera around, or if you want to rotate the building you're making - hit done on the menu in the top right corner, click the building again, click the move button, and now you can rotate the whole building (and the grid) using the Z key. Click it for 90 degree increments, hold and move your mouse to rotate freely.