Download the *.apk file of your App and copy it to your local storage on the PicoPix.
Start the “Media Folder” Application on the Homescreen of your PicoPix and navigate to the *.apk file.
Doubleclick and follow the instructions on the screen to install it. After successful installation it will be available under Apps on your homescreen.
You need to active “untrusted sources” in the settings menu.