Once you have chosen an instructor and booked a lesson, you are ready to meet your instructor and start learning. Your first driving lesson generally involves being introduced to the controls of the car, learning how to make the car go and stop and maybe some basic steering and gear changes. Some people pick it up very quickly, others take longer but that does not mean that those who take longer are worse drivers in the end.
At the end of the lesson, you should feel confident that you have learned something and that your instructor is in control and has put you at ease. Cars are lethal weapons both for those outside and those inside so you have every reason to be nervous! It is important then that you feel comfortable and safe with your instructor.
How many lessons is normal? According to the DSA those passing their test have had an average of 47 hours of professional tuition plus 20 hours of private practice. This may seem like a huge amount and would cost a lot of money (with lessons costing an average of £20 an hour, it costs around £1000) but what you are paying for is experience both at teaching as well as driving, knowledge, skills and a dual-controlled car! The roads are busy and complicated and you have to learn awareness of the roads and other people's behaviour on top of the control of the vehicle.
See other posts in this topic on getting started, choosing an instructor, learning with a member of the family and taking your test.