Go to the file manager and place the OBB in /sdcard/android/obb.

Can I delete Android OBB folder?

The answer is no. The only time the OBB file gets deleted is when the user uninstalls the app. Or when the app deletes the file itself. On a side note, which I happened to find out only later, if you delete or rename your OBB file, it gets re-downloaded every time you release an app update.

What is a .OBB file?

obb file is an expansion file used by some Android apps distributed using the Google Play store. It contains data not stored in the application’s main package (. APK file), such as graphics, media files, and other large program assets.