How do I make her into just a friend?

Ok. I asked a girl out. It’s been long since I’ve been out on a date. It was nice, she is nice and beautiful. But I did not feel chemistry or spark after that time. I am yet to call her but I don’t know how to go from here so that we see each other as friends and no pursue anything else.

How do I do this?

I am not ready for a relationship and with her it would have to be one. I really worry about her thinking badly of me, I do not want to hurt her or lead her on. Any advise?