copy what pre made vivs are like with their structure. make a basic 'shell' with melamine/conti board by screwing it together. this can get damp & be wiped clean plus it's not porous so won't hold bacteria allowing it to breed. so you have a top bottom & two sides. add hard board or ply as backing to square up the frame with tacks. cut a hole in the back & add a push in vent cover or cut several holes in a line for a horizontal vent cover. use 2"x1" peice of wood top & bottom at the front of the viv to attatch the glass runners to (4 or 6mm). use contact glue to stick the runners in to place. silocone all inside inner edges & allow to go off for 24 hours. add glass or perspex cut to size. make sure the runners are the right way round as in the deeper one at the tp shallow at the bottom. measure from the bottom runner (where the glass/perspex door would sit up to just over lapping the top runner. also make sure the doors overlap when closed so u can add a lock if needed - basically they dont want to meet in the middle.
B&Q do conti board in 6ft & 8ft lengths 12",15",18",24" wide. from £6 up per sheet the longer & wider the more expensive. you would need:
x2 8'x2' conti board for the top & bottom. x1 6'/8' x 2' conti board for the two sides. x1 2' x 4' hard board for the back. x5 push in vents x1 box of 1.5 " screws contact glue x1 8' length of 2"x1" wood x1 top runner 4' (4mm/6mm) x1 bottom runner 4' (4mm/6mm) x1 silicone sealent & gun x1 box tacks x2 glass or perspex doors
i now a site that has plans that you can follow and get a 2 good size vivs out of 1 sheet of board. B&Q will do all the cutting for you for 50p a cut. first 5 cuts are free. BARGAIN!!!!!!