Welcome to officiating and have fun! You will love it.
Here is what I tell new officials their first night:
You know what the rules of basketball are. 95% of everything that happens is real simple. Out of bounds, foul, travel, etc. Let your partner worry about the tricky stuff. Here is what you do:
1. Make good eye contact
2. Blow your whistle
3. Call what you see
4. Try your best to stay in your area, but that will come with time
5. Have fun.
You do that, and you will have a successful first night.
Just blow that whistle.