How do I get this one girl to talk to me?

[Ruben H D]

I only seen her sometimes at lunch, mist of the time at pe,music,art n computers I dont know what her nane is but I think its amber so shes cute. I know what to say to her but the main problem is public and friends are near her so whatelse can make her go or automatically to somewhere private so I could give her my phone number. A little help please!?!