iOS Help with an app.

[emf0401]

Hello, I'm starting making an app for a website that I own. I know some about programming with xcode but there's a lot of stuff that I don't know yet.. Mostly I have almost everything figured out for the app but I need to add to the app a way to sign in and sign up to the website and also a way to pay with credit card. I don't know how to start with all that.
I have tried to look some videos but I didn't see anything similar to what I want to do. I would really appreciate if you could explain me it, or send me some kind of help.
You also could answer to my email: marinemilio@me.com
Thank you very much, Emilio

Note: In that website people can buy tickets for concerts and stuff.

 

[amorya]

You'd get better responses if you tell us some more about what you've got already, and then what specific problem you're getting stuck on (including any error messages you're getting).

At the moment your question is too vague to answer. You'll need a REST web service — do you have one already? Is your question about how to write the server component of a web service, or is it about how to talk to one via iOS?