How to install the KeePass2 plugin?

Question

KeePass

The goal is to put a KeePass2 password manager on Ubuntu 16.04 with the ability to sync the password database to Google.disk, which a plugin called KPGoogleSync should handle .
But when the program starts, it swears with this window:
Poryskav found advice on the net that you can put the full mono package sudo apt-get install mono-complete, but alas, this did not give any results.
Can anyone help clarify this issue?

Answer 1

Does KeePass2 itself work? Isn't it easier to just install google drive, and connect the key file locally from the drive folder? Everything works for me according to this scheme, though through dropbox.