Do you have feelings for her? If yes, then talk to her. What are you waiting for? She gave you all the signal that you need to approach her. Next time you see her say, Hi, [name]. Are you free friday night? Wanna go out with me? Then pick her up, take her to a park or wherever silent, then grab some food. Start sharing stories with her. Ask questions. Get to know her. Then after assist her going home. Get her number then go on from there.