If you are unable to install Teamup app for Android from Google Play, you may download the Teamup APK directly.

Here are the steps.

For Samsung devices

1. Go to Settings > Apps
2. Tap the three dots at the top right: ⋮
3. Tap Special access > Install unknown apps.
4. If you have saved your downloaded APK to your device's My File folder, toggle it on:
   
     
   
   If you are downloading the Teamup APK from a browser, tap that.
   
   
5. If prompted, toggle Allow from this source on.

For non-Samsung devices

1. Go to Settings.
2. Tap Apps & notifications > Advanced.
3. Tap Special app access.
4. Tap Install unknown apps. Tap your local file location where you have saved your Teamup APK or the browser from where you will download the APK, tap that.
5. If prompted, toggle Allow from this source on.