If you’d like to target specific countries, you can do so by selecting your desired country in the “Choose Audience” section when setting up a new Acquisition Campaign. This option is located at the bottom of the page.
Something to keep in mind: Targeting a new country that you don't see many (if any) sales from is not something we typically recommend, but if you’re set on reaching a new country, just know it often takes time and consistent spend before you’ll see results.