First you need a provisional drivers licence - this allows you to take lessons, sit your theory test and finally sit your practical test.
You can get driving instructors from one of the big schools like Red or Bill Plant etc or look locally for more independent ones, all should be able to provide a suitable car to teach you it and I'd expect fees to be about £25-30 an hour (ask people you know who they passed with and recommend)
As a rough average you should expect 30-40 hours tuition to pass.
You can basically start at 17, there are some exceptions for people on mobility allowances etc who can start at 16 I think, but 17 for most.
You can practice in a parents car but they need to be present and have insurance to teach you (I think you can get this in your own name too, but not sure, never had it myself, just google learner insurance)