You do your CBT and then you can ride anything up to 125cc with at most 14.6hp for two years before you have to retake it.
Then you have to do your theory test which contains 50 multiple choice questions and a hazard perception test.
Now we're on to the test proper! There are two tests, Mod 1, which is slow speed manoeuvers in an off-road test centre, and Mod 2, which is the on-road assessment.
If you're under 21 then you'll be restricted to bikes with a maximum of 25kW power for two years. If you're over 21 then you can choose to do Direct Access, where you take your test on a larger engined bike in order to allow you to ride any bike after you pass.