|Rolf Connect Math & Numbersense||rc-math-latest.apk|
|Rolf Connect Coding||rc-coding-latest.apk|
Go to settings -> security -> Install Unknown Apps
Select the browser you will use to download the app and go to step 3.
Do the same for "My files" or another file browser your use
Slide "Allow from this source" to on
Download the app from this site and install it