Tech I still dont fully understand

Servers: I still don't fully understand how to spinning up a server actually works even though I've tried it multiple times
Go lang: I've tried for some time, people keep on talking about how easy it is, but pointers mehn! still find those very confusing
Docker: Know what it does, but never played it a lot.
Sass: Never had the opportunity to work with it really, most of the features I need is available out of the box in vanilla CSS