I can heartily recommend https://linuxjourney.com/

It'll guide you through essentials towards more advanced topics - all while thoroughly explaining all the steps in a very intuitive manner. Helped me through basic training in Linux, so to say.
While, if memory serves, it is Ubuntu based, you should be able to directly apply in PopOS.

Oh, and a word of advice, be prepared to tinker and experiment. Its an initial steep learning curve. But man is it ever satisfying reaching the level where you, by heart, throw commands at the terminal to do what you want!

Glhf!