Affidavit construction help?

Hey I need help writing an affidavit supporting proof of a previous residence to get an exemption for application for a government job. I was sent letters that I did not sign-up for selective services, saying I had no response and was showing negligence, but in fact they were sending them to a former residence. I need to show proof that I was at the residence I claimed. I have school records to prove my residence, but i need help with the form and type of affidavit I need to fill out. Any help would be appreciated, like some sort of affidavit template I should follow.