Yes I'm new here and I'm just trying to figure out how this app works.

Can someone help me with some input on using a basement that's under a old barn for setting up a 48×48×80 grow tent?

Sure.

You need a light, 600w-1000w hps or a good LED.
You need a filter and fan to extract heat and moisture outside.
You need some circulation fans.

That's the basics.

Try the grow room design subsection if you have detailed questions.

Welcome to RIU