hi, it would be an easy task for you as you have US licence and driving experience. Which is the driving school through you applied for the test? if you applied for a direct test, you can demand for a hourly basis or day basis class. When I applied for direct test, I requested for a one day(2 hrs) class, cost me 250 QR. I practiced 1 hour inside the driving school for L - ramp test and parking. Rest one hour I practiced through the roads, mine was Gulf Driving School. Where the entire two hours you will be accompanied by a regd. instructor of the school.
about the test, within the driving school you have L ramp and parking once you pass both next is Road test. Where you drive the car and the vehicle inspector sits near to you. He observe you for proper signals, use of mirrors, speed limits,and so on. i think after your one day Practice with an instructor , you will get an idea about it. if you need any more clarifications please feel free to ask me, I can help you as I know.