You may get errors while installing these APK files. One of the errors is shown in the following screenshot:
Here are the tips to solve this issue:
The first step is to enable installation from Unknown sources, as shown in section 1 of the following figure:
Install an Android app called APK Editor, which can be downloaded from following the link:
https://play.google.com/store/apps/details?id=com.gmail.heagoo.apkeditor&hl=en
You can also buy ...