Order options under "Extras"

I’m trying to understand what the “Order” options are in the “Extras” section. The documentation on the website doesn’t even mention anything.

When I hover over the question mark icon, it says “The field group with the lowest order will appear first.” but doesn’t provide any information about how/if you can modify this.

Can I get some clarity please?

https://www.ads-software.com/plugins/custom-field-suite/