How to use an effect plugin?

Well, I added the effect via the Inserts section in the Inspector, as outlined in the manual.

The plugin appears in the inserts tab and everything, but I still have any change in my sound… (print screen attached).

I tried with a third party plugin and a native one from Cubase. Same result.

Taking the opportunity to ask a probably stupid question: can I use an effect plugin on a midi track, or will it only work with audio?

Thanks for the patience.