Go to the Licence Center.
Complete the licence tests to get Domestic B licence.
Even if you do this all bronze you will win a VW Lupo 1.4
You now have a car.
If you wish you can achieve all silver or all gold in the licence test and you'll earn an additional car for each level.
If you do all gold to begin with, you'll earn all 3 cars (1 for all bronze, 1 for all silver and 1 for all gold) simultaneously.
If you complete Domestic A licence, followed by International B licence, you'll earn a couple more cars, (potentially 9 in total if you do gold on each test) and with the International B licence you'll be eligible to enter the first part of the mission hall, you can do the missions as many times as you like and you'll earn credits for each mission that you pass.
Hope this helps.
This issue has been discussed many times before here, so there's little scope for doing it all over again.
No offence meant, but this thread is being closed now to avoid re-covering old ground.