Help with problems with re-packaging resources and google-play-services_lib location?

I've seen some answers that fix the unable to re-package resources error, and also the AndroidManifest.xml file. For that I'd have to copy the google-play-services_lib to the Plugins/Android, but I don't know the full location of google-play-services_lib, or if it's in my project or my pc. In resume: Where's that google-play-services_lib folder? Is there a permanent fix to the error? I'm a complete beginner in Unity, I've just been doing this cardboard VR app for three days for a school project, and it's due next week, so I hope you guys can help. EDIT: This was my error:

Error building Player: CommandInvokationFailure: Failed to re-package resources. See the Console for details. C:\Users\Usuario\AppData\Local\Android\sdk\build-tools\24.0.0-preview\aapt.exe package --auto-add-overlay -v -f -m -J gen -M AndroidManifest.xml -S "res" -I "C:/Users/Usuario/AppData/Local/Android/sdk\platforms\android-23\android.jar" -F bin/resources.ap_ --extra-packages com.google.android.gms:com.google.vr.cardboard:com.oculus.Integration:vr.gvr.platform.unity -S "C:\Users\Public\Documents\Unity Projects\new cardboard test\Temp\StagingArea\android-libraries\google-play-services_lib\res" -S "C:\Users\Public\Documents\Unity Projects\new cardboard test\Temp\StagingArea\android-libraries\gvr_android_common\res" -S "C:\Users\Public\Documents\Unity Projects\new cardboard test\Temp\StagingArea\android-libraries\ovrplugin\res" -S "C:\Users\Public\Documents\Unity Projects\new cardboard test\Temp\StagingArea\android-libraries\unitygvractivity\res"

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I don't even know anything anymore at this point. Please send help.