You can edit your cron jobs by running
crontab -e
Related Posts
How To Install Linux, Apache, MySQL, PHP (LAMP) stack on Ubuntu
https://www.digitalocean.com/community/tutorials/how-to-install-linux-apache-mysql-php-lamp-stack-on-ubuntu
phpMyadmin installation and configuration
https://docs.phpmyadmin.net/en/latest/setup.html#setup_script