NC permits

Cut and pasted from http://www.ncdot.gov/dmv/driver/commercial

You must be at least 18 years of age (21 for operations that require a medical card) and possess a valid Classified A, B, or C license.When operating a commercial vehicle with a learner permit, a licensed CDL operator, with the proper class of license, must be in the front seat beside you.
A Learner Permit is valid for six months with a limit of two permits in two years. If your permit has expired over thirty days, you will be required to retake all written tests prior to the issuance of the second permit.

 

Study the manual and take the practice tests on here. If you can pass the practice tests, you can pass the real thing.
One hint. When taking the test at DMV, skip any questions you aren't sure of. It will go back if needed. But once you hit the minimum amount needed to pass, test is over. Can't remember the numbers,but something like 20 right out of 25... once you hit the 20, test over....