Add new Country

I’m a green horn… Looking how to add missing Country to the Location selector. In my ase I need to add Bonaire, the nice little Caribbean island to my Events list.

I’ve crossed this post:
From the Tri.be support forum
http://tri.be/support/forums/topic/add-a-new-country-to-list/

“Have you taken a look at the “Use a custom list of countries” option on the Events > Settings > Defaults page (admin side)?”

BUT there is no such “custom list” to choose in the latest version. Can somebody please explain me in detail how I can manage this.