can i use 1st edition books in 2nd edition games? or vise versa?

I'm new to role-playing and this is my first time hosting and running a game, can i use opposite books from different editions or do they have to be the same edition? Also any tips on running a game on her would be appreciated, thank you. 

The forums here are more for using Roll20 and such while your primary question (different editions) is about a game system which is off topic for the forums. I would recommend hopping over to Reddit and finding an appropriate sub-reddit there to ask your question.

What Pat said. But to also answer your question, it's rarely a good idea to mix and match editions, and if you're new to both RPGs in general & running them, I suggest you stick to books from one edition alone, ruleswise and for stats. Of course you can take inspiration from books based on other editions, but the rules and stats are not likely to be compatible, so I'd leave mixing and matching for later when you feel you have a good time with running things based on one edition. You wouldn't mix the rules of soccer and american football to make a new sport if you haven't played either, especially if you're unsure how similar they are, right?

ᐰndreas J. said: What Pat said. Even though I did comment about Roll20 specific I didn't answer his question in public but did send him a pm about it. It was similar to your information.

The answer is Yes, James, you can. I regularly play a cross-over, mix of different game systems or editions on here. It's similar to what you could do at your tabletop at home. Feel free to use whatever rules or books that you want to, as Game Master / tabletop owner / campaign creator, on here.