Setting up Git: Frustrated

I have been successful with creating a Github account. I have not uploaded anything bcos my html and css have to improve, I don;t want to uplad projects that need improving.

I tried to setup Git after watching this video https://www.youtube.com/watch?v=RGOj5yH7evk&t=192s from youtube and I have failed. I downloaded the Git-2.42.0.2-64-bit.exe file and tried to install it, I could not proceed bcos it has too many options that I have to select, some I selected bcos they are recommended and most of them are confusing. I need help with Git. I tried a different method using command prompt and it also failed, it tells me that my username is not recognised

I dont know what to do anymore