Flirting should be spontaneous and you don't need step by step advices at all. You have it all inside you but you're just nervous. Just think of something to relax you and you will be flirting in no time. Don't think too much or think about her reactions too much. I can't give advice because I'm not in your shoes and I need to see how she flirts back too.
Not too hard man. Just show her your interested in her and start up a good conversation. Smile at her,laugh, express yourself and go get this girl man. What are you waiting for its not hard, should come natural if you like her.