Our analog mastering console plugin bx_masterdesk is a stereo only effect so therefore, you will not able to instantiate it on mono audio tracks in Logic. In order to find the plugin in your plugin picker dropdown menu, you first need to convert the mono track to a stereo track by clicking on the small circle next to the input selection button. After you do so, go back to the Plugin Alliance category and bx_masterdesk will then be able to be instantiated on this track.