See the scan below

First step is to check what you are sending.
For photos and SASE's, check documents.
For Gifts, obviously check gifts.
For anything else, check other.
For the Commercial Sample box, ignore it. You won't be using it
Fill in the rest of the blanks as indicated in the scan.
Unless you are sending something other than photos, you can ignore the value and weight columns.
Take this form, and your parcel to the celeb to the post office. They will attach the green part to the parcel, and they will then take the white part.