Depending on the individual, your first driving lesson could either be something you are looking forward to or something that makes you feel very nervous and apprehensive.
Here is some information that would help get you prepared and make the day go much more smoothly and earlier.
If you've never driven a car before, and your lesson is with a UK qualified approved driving instructor (ADI), then it will usually be a controls lesson.
This is basically an introduction to the Cockpit Drill (DSSSM) and the controls on the car. You can prepare yourself for this driving lesson by learning the cockpit drill and even practice it in someone's car. If you do have someone willing to help you, also ask them to point out what the 3 pedals (on a manual car) do, explain the gears, handbrake and indicators. If they are willing, ask them to start the engine and allow you to press the accelerator pedal, you will be surprised at how little pressure is needed. If you do this homework, then the instructor should really only need to ask you a few questions, see you demonstrate the Cockpit Drill, and then proceed to the next lesson which will be Moving Off and stopping.
If you ignore my advise, or are lazy and can't be bothered, then the instructor will probably have to spend about 30 minutes explaining this to you, leaving you only 10 - 15 minutes of practical driving! You could use that time to better advantage learning more important practical driving skills, especially as a complete beginner If you are willing to put in the work, you spend less time (and money) on the theory, and more on practical issues.
If you also take the time to learn the POM and MSM routines by search for these on my blog, it will greatly improve your knowledge and help you progress much quicker there by reducing the number of driving lessons required to pass the test.
If you have any questions as a new learner, try searching my blog first, if still not sure I welcome queries via email or contact me on Twitter: UKADI_