How To Sign Up For Amazon Prime Membership As A Medicaid Senior

I am a Senior Medicaid member and I have been trying to sign up for Amazon Prime with the advertised 50% discount, but I cannot find where to go or which page to use in order to activate this offer. I have checked the site, but it is not clear how a Medicaid member is supposed to verify eligibility and start the discounted Prime membership. I request clear guidance and an easy, accessible link or instructions so that I can enroll in Amazon Prime with the 50% Medicaid discount that is being offered.