THDA has forms on their site. You'll need a notary and a trip to the Register of Deeds office in your county. Lean on the Register of Deeds office for the answers to your questions beyond this starting process.
You can get one to print out and fill in off the internet. Type in search engine : affidavit of affixation and you should see several sites to obtain one from.. You can also go to the county registers office and request one.
Hope this helps! Good luck,,
Tina Evans, Broker
LUNA REALTY GROUP