I signed up to the site and it looks like there are two different types of requests that can be made. FOIA and Privacy Act request. Since I am getting my own records it looks like Privacy Act request is more appropriate?
It looks like I also need to attach a "Certification of Identity form" which I found here.
https://www.oig.dhs.gov/sites/default/files/assets/PDFs/OIG_Cert_Ident_Form.pdf
I think I also need to attach a photo ID like a drivers licence or a passport card?