Obb is not an Android installation package. It’s an application data file.
You have apk file and OBB file
1.Install apk file
2.Go to the android/OBB path in your storage and create a folder with the package name
Note: If you have installed the application in the phone memory, you must create the folder in the internal memory, otherwise you must create the \U0001f4c1 folder in the external memory card. If you don’t have any idea about storage, create a folder and put OBB in both internal and external sd cards.
If you don’t have any idea about the package name, then you can get it from the play store link.
Example: If you have Plant vs Zombies 2 game and installed in external storage go to sd card and create folder com.ea.game.pvzfree_row in Android/OBB folder and put OBB file there
3. Launch the application. That is all.
Note: This technique doesn’t always work