<human>: Give me a shortened version of the text

My friend(23m) and his girlfriend(23f) want to introduce me(19m) to the girlfriends little sister(21f), Ashley, and set me up with her because her current boyfriend will be moving away soon. I'm a little nervous because I don't have any experience with relationships and just a little sexual experience. I'm fairly handsome and seemed to be doing good at all the sexual stuff I did with another girl a long time ago, but she escalated it and flirted with me. I just kind of went along with it. But I realized I really don't know how to escalate.

I went over to their apartment last week for a party and Ashley seemed pretty cool and we talked for a minute, but she spent most of the time sitting cozy next to her boyfriend. I didn't want to be trashy and hit on her when she's clearly still with this other guy. He'll be leaving in the next week or two and my friend and his girlfriend will probably invite me to hang out soon after that.

I realized I don't really know how to flirt or escalate any interaction with her. Plus since we'll probably be hanging out with friend and girlfriend, do I just hit on her in front of everyone? I mean I just don't know what to do I guess. Should we hang out once or twice and then I ask her on a date or something?

Does anyone have any general tips or advice of how to flirt or what to do assuming that we all are hanging out and things are going well? Also anything I shouldn't do? Thanks for the help.
<bot>: Hanging out with friend, his girlfriend, and her little sister, but I'm nervous because I'm not sure how to flirt or hit on her.