You can instantiate a plug-in on any kind of track or grouped tracks in Cubase (audio, instrument, effect, master, etc.). In the following steps, we'll use AmpliTube 5 as an example, and instantiate it on an audio track.

1.  Make sure you have the Left Zone showing. If it's not already showing, you can hit Command+Option+L to reveal it.
2.  Select the Inspector tab at the top of the Left Zone, and the Track tab at the bottom of the Left Zone.
3.  Click the name of the track you wish to instantiate the plug-in on to select the track.
4.  In the Left Zone, click on Inserts to reveal the available insert slots.
5.  Click on an empty insert slot, navigate to the plug-in you want, then click on it to instantiate it. You'll find AmpliTube 5 under Distortion.