You have to do a driver theory test for the "C" category. You also need to go through a medical. You can use your own doctor. Then you can apply for a provisional licence.
Once you have your provisional you need to apply for the driving test and get lessons. There are no loopholes like for cars. You must have a qualified driver with you. When I did the test a couple of years ago lessons were about €40/hour. Don't know what they cost now.
A good instructor will probably advise you on passing the test better than I can.
Good luck!