You are required to hold a valid driving license to be able to drive legally on UK roads. In order to obtain a driving license you must pass test / exam. Typically to pass a test / exam you typically send some time with an ADI (Authorized Driving Instructor) who will have the knowledge and experience to support your learning ahead of the test.
There are 27 skills or sets of knowledge you must be proficient in to be able to pass a driving test
Each of the 27 skills has 5 levels of progress, you should only take your test when each of the 27 skills is at a progress level of 5. Those 5 levels of progress are as follows
There is not a legally mandated minimum time you need to speak learning before taking a test, the amount of hours you will need to in order to pass the driving test will vary by person