I'm no expert but this seems like a pretty good crash course to me. One thing I still tend to use a lot when fiddling with cron jobs is crontab guru [1], which is very helpful for figuring out scheduling.
Another great resource, especially when you have a lot of cron jobs, is https://cronheatmap.com which shows an hour-by-minute grid of one day, and how hot each of those minutes is for your given cron schedules.