It's fine you took the pic with the bike upside down - it would be considerate if you flipped the photo before posting.

You managed to unspring the derailleur, which can be done without the spring breaking or being removed, but could be from the end of the spring that inserts into the derailleur body breaking. Yes, compare to a working 105 and you should be able to see your error, or get someone at the shop to show you how you went wrong.