I'm going to upload my game to google play, but there's the part where I'm stuck

I packed my game because it was 400mb, I used google pad and aab was 100mb, it also created an obb file, is it enough if I upload aab to google play? Or do I need to install the oob file too? If necessary, how do I install the obb file?

Have a look here: Add or test APK expansion files - Play Console Help

If your app needs more than 100MB of memory, you can use expansion files to store additional APK assets. You can store two expansion files per app. Each expansion file can be up to 2GB in size.

APK files have a maximum file size, based on the Android version your APK supports:

  • 100MB - APKs that target Android 2.3 and higher (API level 9-10 and 14+)
    • Users must run Play Store version 5.2 or higher to install 100MB APKs.