Maybe you do not understand what a cronjob does? A cronjob runs a command or batch file automatically at the time or date you want to run it.
You can google for more information to understand the function of a cronjob. This is an example: https://phoenixnap.com/kb/set-up-cron-job-linux
Backups with cronjobs are very easy with aaPanel: simply select database or site and the time/date it should run, e.g. every day at 11:07pm.
