I don't know how old you are, I am assuming you're at least 17-18. First, you must have birth control. If you don't, there is a huge chance you can get pregnant. (Enough said about the birth control.) Privacy is key. Find a place where the two of you can be alone for at least an hour. Next, if you want to make love to him, you have to send the right signals telling him you are ready. You need to arouse him. Start by flirting with him. Then, start kissing him. Kiss him on the lips, kiss his neck (right behind the earlobe), and while you are kissing him, hold him closely. While holding him closely and kissing him passionately, move your hand down south and start rubbing his genitals (through the clothing). While all of this is going on, he will probably be doing some stuff of his own to you. If you are feeling comfortable enough at this point to move on, put your hand down the front of his pants and fondle what you find. All of this stuff so far is enough to completely arouse him. If you are sure you want to go all the way, now is the time. Start by undoing his pants/belt/zipper. Then pull them down. Take his shirt off. Take his penis into your hand and gently stroke it. Then lay him down on the surface (bed/floor), and undress him the rest of the way. He has probably undressed you somewhat, so don't be surprised. Undress yourself the rest of the way. Next comes the big kahuna...lay down beside him, and stroke his penis some more if you would like. This will make him very hard, and guys like that kind of stimulation. Finally, either roll on top of him or pull him on top of you and let him enter you.
That's it. This is just one scenario, and it may play out a little different.