I installed zone manager and am trying to set a PVP dome on our PVE server. (I have the squidGames plugin running but the turrets wont shoot players) So I am going to try and cover the prefab with a PVP dome.) I can create a dome and use the edit command and it says I'm editing, but I see  no where to actually set the dome size. Is there a UI that should popup? I have every perm set for my use.

You should see a wire frame circle around your zone after adding a new one.  It will go away after 10 or so seconds, so you'll have to to type /zone to see it again. To set the size you type /zone radius and then the size you want. For example, if I wanted a large zone I would type /zone radius 80. You should then see two wire frames.  One showing your original size and another showing the new size.  Just keep doing the /zone radius command until you get the size you want. 

Hope this helps.

It does. How would I set a rectangular dome? Thank you.

Then you would use size instead of radius.  If I wanted to create a rectangle with a length of 50, a width of 60 and a height of 20, I would use /zone size "50 60 20". But then with using a rectangle comes the added task of rotating the box so it fits properly around your building. Do this by typing /zone rotation 20 (or whatever value you need). You can n use negative numbers to go back if you over shoot your target. 

Thank you very much. I appreciate the help.