How can new currency (Ethiopian ETB) be added to Currency Master for set up

How can new currency be added to Currency Master to have it show up as an option during setup? Thank you.

For that to happen you can create a new Github issue here requesting for the currency:

If you just want to set up the currency in ERPNext, you can search Currency in the search bar. This should lead you to the currency list page. Click on New and create a new currency.