I'm assuming you are a guy. I too am a bisexual man.

You've been honest enough to say that you don't know what you want, but that really is the core of any relationship. As a virgin, everything will be new. Most bisexual guys are really interested in guys for the sex, and mostly it's an attraction to the penis. You could just start out experimenting, which considering the guy you are chatting with is looking for a FWB is right in line with the situation.

You could start by meeting up, finding out what it is like to be physical with another guy. Try kissing, humping, give and receiving oral, even giving and receiving ****. Find out what you like, and be honest with your partner.

Eventually you will know if you want more than a sexual relationship, then you can take things to,the next level, with your friend or another.

You are at the start of a long and special path, exploring your sexuality. Walk in the direction that make you feel comfortable, whichever path takes you there.