How Do I Go About Getting An Endorsement?
Get the contact information of the person you are interested in getting the endorsement from. Either send a physical manuscript or email a pdf to them. Ideally, you should send out a few, as it doesn’t hurt to get more than one. The more the better! Once you have sent your work, they should send you a letter back with their approval, often on their own letterhead. It may be in typed or handwritten, physical paper or email saved as a pdf. This will be a page in the book, generally, in the beginning, preceding everything else. If you are lucky enough to acquire more than one, put the most revered or knowledgeable person first.
Keep in mind that some people do not give endorsements as a personal policy. If this happens, do not take it personally or become offended. It is not uncommon and is applicable to anyone, not just you. If you know of someone who is an expert in your subject matter, try getting an endorsement from them as well. It never hurts to try.