Need some advice to install a plywood floor over concrete please.

I have been researching a lot and would like to install a plywood floor over concrete in two bedrooms in our basement. I have seen many blogs and read a lot, and know it can be done, but, need a bit of help. I have read in some places that you NEED a vapour barrier to put over the concrete before installing the plywood and in other places to just glue the plywood to the concrete floor. We have been in our house for 5 years now and haven't got any moisture in the basement, and there has definitely been opportunity. This plywood floor would be the floor, not a subfloor. I have read about nailing it to the concrete, but that could wreck the look of the plywood, do I think gluing is the best, but, can I just glue straight to the concrete or if I out a vapour barrier, glue it to that? My concern with gluing it directly to the vapour barrier, is, do I need to attach the vapour barrier to the concrete somehow? And if not, will it all shift? I hope this all makes sense. Thanks for any help and advice anyone can give!
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