Open the Find section on the home screen, and then select an app. Choose Get to download it. To download apps from Amazon's website, find one through a search and then select Get App. This article ...
Amazon is weirdly warning only some customers that they will not be able to sideload apps on the new Fire TV Stick HD.
As great as these devices are, technology always moves on, and Amazon has set a timeline for when it will stop updating some of the existing models.