1 hour glucose test

What should I expect? I have no idea what it entails except she said to avoid carbs before. She did say it was non-fasting but I haven’t had much of an appetite lately. Would it be okay if I did fast?

I’m doing it at Quest Diagnostics if that makes a difference.

Oh also I’ll only be 6+5 when doing it. She said I had to do it in my first tri because my father is diabetic.