Excel Table beginner problem

Hello
From an excel class, I got a worksheet and another sheet with the solution. But I just do not know, how to do it, I donīt even know what I would have to google to be able to understand the solution.

Maybe someone here can help me really quick? A few keywords as to the methods that were used here, or a very simple explanation what my teacher did here would really help a lot!

I will attach the "worksheet" (3.1. excel table) and the "solution" sheet (3.1. excel table lsg).

The exercise I am having problems with, is the sheet sheet2, 3.2 excel table and exercise 2.

Thank you already so much in advance!