First and foremost, you need to be a professional member. You will not be allowed in warmup without it. As far as credentialing, up until this year only Worlds coaches needed to be credentialed. However, I've been hearing it will be required for all coaches next year. For that, you have to take a written test (it's technically online) for each level and section you require (building and/or tumbling). You also have to take 3 mandatory online classes on concussions, heat safety and something else that I can't remember. Once you complete all that, you'll need to take the hands-on portion of the test. Only after passing both written and practical will you be credentialed.