Pure midi plugin and Cubase

Hi to all.
Suppose that I want to write the simplest midi filter plugin (it receives midi data, it returns midi data but maybe it shifts the note pitch by a semitone). What is the correct JUCE project to setup? I’ve tried (and correctly compiled) a Plugin-type project with midi in and out capabilities and I’ve built it both as a VST and a AU plugin (I’m on a Mac).

I can see it in Cubase, but how do I insert it so that whenever I play a note on my external midi keyboard the actual recorded note is shifted by a semitone because the plugin is filtering the midi data?