What’s the equivalent of the crontab command in the K1

I want to automate the backup of my Creality K1 so that every 30 minutes I can backup it to my GitHub. The logical would be to use the “crontab -e” command. If I do that I get this message: “crontab: can’t change directory to ‘/var/spool/cron/crontabs’: No such file or directory”. That’s where I’m stuck. How can I create such a routine?