One of the most useful tools on your NGINX server is Cron. Backups, updates, SSl renewals, they're all run using the cron service. And it's not just for sysadmin jobs, you can customize it to include any job you want and run it on any schedule you want.
First, you'll want to generate an SSH key, and login as root to your server. There are guides in the KB on how to do that.
To get a glance at your existing cronjobs, use the following command:
To edit an existing or add a new cronjob, enter edit mode using the following command:
If given a choice of editor, select nano or your favorite text editor.
Type what you want in there, and hit CTRL and X and it'll prompt you to save, press Y for yes, and then it'll ask for file name but just hit enter.
You can also run the following command to switch user into your system user and add user level cronjobs:
By default, sites are added as gridpane, but you can create a custom system user and assign the sites to it. It's ideal to create a unique custom system user for each site.
Here's a great resource for figuring out what time you want things to run: