Welcome to the world of connecting flights. There is almost nothing direct from where I fly, so connecting is what we do. It's not difficult and you'll do fine.
At Buffalo, they will provide boarding passes to you for both of your flights. Hang onto them. You will need the first to get to JFK and the second to get to MCO. In Buffalo, they will also check your bags all the way through to your final destination. You do not need to do anything about your bags at JFK. It works well almost always. Sometimes there is a screw up however, so be sure to pack what you absolutely must have for an overnight in your carry on (medicines, change of underwear, swimsuit, etc) just in case.
Sometimes the flight crew will list off the connecting gates shortly before your first flight lands. If you catch the info, great. If not, don't worry too much. When you get into your gate at JFK, look for the departure monitors and find your flight. Then, depending on the amount of time you have before your next flight leaves, either hoof it to your connecting gate, or stroll over there.
Good luck. JFK is a big airport and can be a little overwhelming. If you need help, ask an airline crew person and they will give directions, etc.