No sure how to explain it....Know exactly how to do it in my head, just not very good writing it down :lol:
Basically you will need 4 hinges (similar to the type that normal doors in your have but smaller versions lol)
depending on how your viv looks etc depends what is hinged. Im currently looking at building one with oak panels and hinging to oak doors on the front with glass panels in the center of them. You can get the glass cut at glaciers and fit yourself with window beading.
Sorry if that doesnt make much sense
The simpliest way as said is to just have two sliding glass/plastic doors
Edit These sort of hinges you will need
http://www.aandhbrass.co.uk/products/door_furniture/hinges.jpg
and just look at a door in your house and basically make a smaller one of that.....
You can then use a bolt lock like this
http://upload.wikimedia.org/wikipedia/commons/1/1b/Bolt_lock.jpg to keep the doors shut, but obviously a smaller better looking one