Do i need to turn in additional information to the state of Oklahoma when i select that i live on tribal land? it had me mail a form but gave me no other instructions?

I have already completed my taxes. i selected that i live on tribal land it said i would need proof. i thought it would tell me instructions and it did not. it did have me print a form to mail to the oklahoma tax commision but it was just a form that i signed at the bottom.