Cron job is an important component for correct Magento performance. It is widely used for running actions that are performed on schedule, such as indexing and caching, email dispatches, sitemap generation, currency rates updates, and many more actions as well.
Log in to the server via SSH. Run crontab -e command to add a cron task. At this point you will see a text editor, where you can add or edit cron tasks. Starting from a new line, add the following record:
*/5 * * * * sh /path/to/your/magento/site/root/cron.sh
Again, don’t forget to insert your own default folder path!
Save the changes and close the file. If you did everything correctly, crontab -l command will show you the newly created task.