You have to pay to do an internship in the UAE if you're not a citizen (aprox 50,000 dirhams which roughly 15,000 US) that's just for them to allow you to write the licensing exam. Oh and if you're on-call and you're not a citizen, they don't provide you with meals, but if you are a citizen, they do provide you with meals (wtf racism to the next level I know).
After you pass the licensing exam, you apply for a residency spot, there's only medicine, OBGYN, family practice, and psychiatry I think (not sure about psych). UAE citizens with lower grades and worse credentials than you will get these spots, if there are any left, you might be able to score a place.
During residency, you'll get paid aprox 10-12 thousand dirhams per month, depending whether you're in abu dhabi or dubai (ad pays more as a general rule). If you're in ad, you get the above mentioned plus housing. In dubai, you're on your own for housing. 10K will not get you a room in the most run down places in dubai, let alone a flat. BUT there's a twist! You see many people apply for residency in the UAE as a back up, they start residency and if they get accepted in the US or UK, they just pack their stuff and leave. SO what did they decide to do to fight this? They deduct 2000 dirhams from your salary and "save it" for you. If you complete your training, you get a big payment of all those 2k adding up over x number of years. If you don't complete training, your money goes to them.
Residency in general is horrible. You're mostly not going to do anything on your own. You're just going to learn by observing.Which is the complete opposite of medical residencies elsewhere.
As for practicing if you're foreign trained, you need to pass their licensing exam (you need at least 1 years(s) of clinical experience in your home country to sit the exam, or you pay 50000 dirhams and get 1 year of experience at their hospitals) . The exam is generally very easy, I don't think that any decent medical student would fail it tbh.
Hope that helped!