An APK file is an app created for Android, Google's mobile operating system. Some apps come pre-installed on Android devices, while other apps can be downloaded from Google Play. Apps downloaded from Google Play are automatically installed on your device, while those downloaded from other sources must be installed manually.

How to Install APK and OBB (Data file) on Your Android Phone?
Install APK on Your Android Phone
First, you need to install the APK file on your android phone. In order to do that, simply follow the steps below:
1. Place the APK file in your phone’s SDcard or Internal memory (preferably external SDcard).
2. Browse your phone memory/external memory and tap on the APK file.
3. Click ‘install’
4. Wait for the APK to install.
5. Do not run the application yet.
6. After a successful installation, you need to place the Data / OBB file in the right place.

Where to put the OBB or Data file?
1. First of all, unzip/extract the downloaded OBB or Data file in your PC or laptop.
2. Copy the ‘Data’ folder and place it into the given path: External SD Card > Android > Data > “paste the folder here” In case of OBB files, copy the OBB folder and place it in the given path here: External SD Card > Android > OBB > “paste the folder here”
3. If you cannot find the OBB or Data folder, you can create a new folder manually.
4. Make sure that the files are successfully copied in your SDcard.
5. Disconnect your phone from the PC.
6. Run the APK file now.