Starting a text with a guy?

I like this guy and we talk at school sometimes. The thing is that he doesn't have my number but I have his. Idk if I would want to ask for it. But I've texted him who is this cause at frat I didn't know it was his number than a friend told me. He never respond. So I don't no if I should text him again but I want to so wat should I say!??? XD thank u all!!!