I wrote a guide on how to use cron on this website
The website is about how to set up a Linux server and how to host things on it so you can own your own services and data and be a independent internet user like the internet was meant to be.
The site is called landchad, Land being "internet land" and Chad as in the meme Chad. A bit tongue-in-cheek but I am kind of surprised that there is no resource out there like this already.