When you are learning to drive there is one path to the official DSA test and that is to take lessons. How you go down this path is up to you but there are two main options:
Option A: take single, 'per hour' lessons, perhaps 1 a week, costing £25, which could take anywhere from 4 - 8 months to pass.
Option B: take an intensive/crash course, completed in 1 week, costing roughly £1000, passed within two weeks.
The option being discussed here is the intensive crash course, arguably the better course but that is for you to assess depending on your needs.