The driving test is split into two parts;
The Theory Test consists of a computerised multiple choice questionnaire and a Hazard Perception Test which is based on video clips. You must pass both of these tests to obtain your Theory Pass Certificate.
You must pass the theory test to apply for the practical test. After passing both the theory and the practical tests you can apply for your full licence.
Before starting to learn to drive it is useful to have an eyesight test (mention you are just starting driving lessons) to ensure your eyesight is up to the rigours of driving.
As of September 2008 the DSA introduced Eco-Aware driving as part of the Practical test, although for the time being it is only used as a guidance and no driving faults are marked against you. Although this was introduced by the DSA in 2008 I have always taught my students the importance of Eco-Driving not only to the environment but to their pocket (use less fuel therefore you buy less!)