How should i ask this guy to sadies??? HELP?

In middle school, i really liked this guy. We talked a little in cles, but not too much. I invited him along with all his friends(including my guy friends) to my pool party last summer. I talked to him, but I think he was more into my friend than me... He's really good friends with one of my close guy friends that i've known for ever. But for highschool, he went to an all boys private school. My school's sadies is coming up and i kinda wanna ask him but i dont know how. I haven't seen him in months, but my guy friends who are close to him say that he will say yes most likely. I don't wanna do something too over the top, but I'm nervous to just ask because i don't know where to do it or a anything. HELP? whats a good way to ask and not be nervous??