Cron trigger tutorial

Can somebody send a link to good CRON tutorial? I found some for UNIX but they assume 6 or 7 groups but KWGT has only 5. And it is also too complicated.

The process should be the same for all corn jobs. I think the only difference is that Kustom uses 5 blocks, which means that you can only do up to a minute interval and not seconds. The tutorial below seems to only use 5 blocks.

https://www.hostinger.com/tutorials/cron-job#How_Cron_Jobs_Work