First Attempt At DIY (Rock Background)

[J-A-X]

I have finished the background, just wanting to know how long I need to wait before putting in the enclosure?

Put it outside in the sun (if you're lucky enough to have some) for a few days, it will make sure any fumes are well gone before putting it into your enclosure. Once it's in, Get the lamps and lights going, shut the doors and come back in a week and stick your head in to see if there's any smell, if there is take it back outside again.
Better to make sure now than have a resident get gassed