I got there at 6 last year. It was my first time and I wanted to walk around and check everything out, take pictures, etc. Remember - even though the TV broadcast doesn't start until 8, the earlier presentations/awards start at 7.
That said, if you don't care about any of that - you can get there at 6:45 and just go straight to your seat and be fine.
Updated On: 6/6/18 at 11:14 AM