Open the "Play Store" application, which can be accessed by clicking the "All Apps" launcher icon located in the dock.
Once the Play Store app opens, search for "TouchDRO" (without quotes)
Select the app from the search results and cLick "Install".
Step 4 (Optional)
Move the app to the main screen. To do so go to the apps, touch and hold the TouchDRO logo; once the view switches into the "drag-and-drop" mode, drag the icon to the main screen.