New to the UAE — How Does Health Insurance Work Here?

I recently relocated to Dubai for work and I'm finding the health insurance system quite different from what I'm used to. My employer has enrolled me on an AXA plan through a TPA called NAS, but I'm confused about how to actually use it. Some specific questions: 1. What exactly is a TPA and why doesn't my insurance just work directly with hospitals? 2. I have a "silver network" — how do I find which hospitals and clinics are included? 3. Is it true that some doctors/specialists might be at a covered hospital but not on my network? 4. What happens if I go to an out-of-network provider in an emergency? 5. I need a GP for a general check-up — is there a way to search by insurance online? I called NAS and they emailed me a PDF list but it's massive and not very user-friendly. Surely there's a better way to navigate this? Any tips for a newcomer would be really helpful. Thank you.