You need to have him tested for frame if the breed is known to carry it.
A vet should also come out make sure he is clear of any viruses he might pass on when breeding if you are considering live cover. If he has never bred before this might not be necessary but if I were a mare owner I would want to see documentation that he could not infect my mare. You need to see proof that the mare is clear also.
Contact the breed organization to see what test they may recommend.
If you have never owned or handled a stallion before why would you want one that is going to weigh over 1500 pounds to learn on?
I would suggest you send him to a stallion station for the first year or two and learn everything you can.
Only an experienced handler needs to handle a breeding stallion before . during or after the act. Those are the most dangerous times .
Be careful and good luck. Shalom