For the first time, select the desired policy group to which APK has to be uploaded to auto-install on the device. 

Click on ‘App Management’ category.

Click on ‘Private Store’ and then click on ‘+’ button tab as shown in the below picture. 

Upload the APK and click on the "Upload" button.

Notice app details in the section. To auto-install the application click "SAVE AND CONTINUE".

Once the device gets the updated policy, the application will auto-install. Make sure the device has a stable network connection.

If the same APK has to be uploaded in another policy within the same application, Go to "Private Store" of another policy as mentioned above and click on ‘Available Apps’.

Notice the app uploaded previously. Select the app and click on the ‘Save and Continue’ button as shown below.

As and when the device gets the updated policy, the app will auto-install.

In this way uploading of an APK in multiple policies can be avoided.