1 . Settings - > Devices and Turn On the " Install Application From UnknowSource " .
2 . Kindle Fire HD connected to the computer . From the Kindle drive on your computer create a folder or directory as your app name . Copy the game file and the software you want to install to this folder . You can download the game software and website www.appstore.vn/a .
3 . After copying is finished, disconnect the Kindle Fire to your computer and start the installation .
4 . Access to Office Suite software on Kindle Fire HD . Select the tab " Internal Storage" to open the Kindle Fire HD memory . At this point in the tab appears on the first row of Tab , you choose " Filter " then select " Show All File " , this time all the files and folders of the Kindle Fire HD memory will be displayed. Navigate to the folder where you copied earlier software and game and proceed to normal installation .
5 . The software you should down ES Explorer or Root Explorer is the second most common file browser on Android for later installation process simpler.
See more at Guide on How to install apps, games for Kindle Fire HD (without rooting )