Easy process. I went in 1 hour early. It wasn't necessary. There were 3 other people waiting inside. Took my token and I was called immediately to submit Birth certificates, PCCs and AoS.
Then I waited exactly until my appointment time. There are no clocks inside so I had to keep the time in my head. I was asked 5 basic questions like living situation, careers, life in the US etc. It took 3 minutes totally. I was approved on spot. I was out of the embassy 5 minutes after my allotted appointment time.
Phones will be turned off and collected by security. Plastic water is allowed. There's restrooms inside. Bring all originals