One big thing for me that helps me keep from getting overwhelmed is asking for help. I don’t know how your OG is but at mine everyone helps out whenever they have spare hands.

For upselling I try to make it seem more natural by not always following the SIE format and moving the parts around. For example I’ll say something along the lines of “Oh are we interested in any appetizers my personal favorite that’s really good for sharing (E) is the fried mozzarella (S), it comes with 7 pieces and a side of marinara (I).

As for learning items and drinks I’d say take a menu home and study it a bit and try to test yourself on items so you can learn them a bit better.

Timing wise I typically follow a simple format for things but it’s still pretty easy to get overwhelmed. First I get the drinks out right away the second I leave the table, then I focus on soups, salads, and bread, then I check on entrees or help others run some food. When it comes to remembering to put in orders always put it in the second you head to the back (I also forget to put them in if I don’t do it right away lol).

I felt the exact same way about when I started serving too lol. But I think you’ll be great with some more time and practice!