Struggling to understand recursion

Recursion is really hard for me right now to understand and I’m just wondering is there a way
I can learn this as I know its pretty important.

Link to the challenge:
https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/basic-javascript/replace-loops-using-recursion

Which step don’t you understand?
Do you understand the description?

Basically I found the description to be hard to understand but I’ve watched some videos online after further searching ( I did to read-search-ask, but followed by more searching )

starting to understand it but realised I need to brush up more on for and While loops too!

sorry if this question was a bit vague and open ended but I figured it out!