Not exactly sure what kind of guidance you are looking for. I took the 510 exam in May. Here was my experience:
First, you must register with the API ICP program at api.org and submit an application for the exam. In they application, they will ask for your supervisor's contact info and will send him/her an email asking to confirm your job duties/work experience. Once you pay the fee and API approves your application, they will send you a code to take to the Prometric test center website. Use the code to schedule a time to take the exam within the exam window. When you show up on the exam date, Prometric will have you empty your pockets, give you scratch paper and a cheap calculator and take you to your computer terminal. The test has two parts, a closed book section and an open book section. For the open book section, the reference materials are available in digital format on the same computer you are using to test (unfortunately, the ctrl+F function is disabled, but the ToC is hyperlinked). There are 125 questions between both sections, and on the May exam, 86/125 was the passing score.