To install Minecraft APK on your Android, you need a few settings. First, go to "Settings" on your phone, open "Security" or "Privacy" and enable the "Unknown sources" option (or something similar, depending on the model). This is necessary so that you can install files not from Google Play. Then just download the APK file from a normal site, for example,
Minecraft APK, and open it. You will be prompted to install the game - click "Install" and that's it, the process will start. If something does not work, try restarting the phone. And also check that the file is from a trusted site, so as not to get viruses. In general, everything is simple!