I too could have had my Canadian license certified but did not want to make the 10 hour bus trip to SD. Pay licensing fees at Banreserva, go to licensing office in Puerto Plata. Talk to the guys outside about the class that explains the test questions and gives you the info to answer the the weird and unexpected questions. Go into the office to register, test eyes, test blood take theory test on a computer. If you pass you get a temp learners permit. Go pay for practical test at Banreservas. Go back to office in 4 weeks and take the practical driving test. All done.
There are examples of the complete theory tests on Youtube.com. My very limited Spanish was not an impediment. I was quite surprised. I understood the class and the computer tests. The class is basically, "this is the question", "this is the answer". This word means fine, this word means infraction etc. One of the head-scratcher questions I got : "It is permissible to honk your horn at animals on the roadway?" Answer: "No."