Setting up a new cron job.

With 3.10  there are already CRON jobs that run

Where or how can one of these be setup ?  can someone please provide some details

Thanks
Jonathon

Admin > System > Scheduled Tasks

yes, How do I add my own to this very screen

These are not actually "CRON jobs".  They are nopCommerce Scheduled Tasks.  You can custom code a plugin.  See dev FAQ page.
(If you really want to use CRON, your hosting provider might have that ability in their control panel)

If you have any problem with the cron job settings, you may try http://www.easycron.com

Hi everyone.

We've released a new plugin that allows to schedule NopCommerce tasks using a CRON expression.
Checkout the demo here https://ellasoftware.com/cron-tasks-nopcommerce