The plugin should show up in your DAW as Sonarworks Reference 4. If you can't see it, please try relaunching your DAW/restarting your computer (suggested for macOS) and/or rescanning your DAW's plug-in list.
NB Reference 4 supports VST2, AAX, RTAS (Windows), and AU (MacOS) plug-in formats
Please make sure that your DAW is scanning the correct locations for your plug-ins. Reference 4 plug-ins will be installed in the following directories:
C:/Program files/Common Files/Avid/Audio/Plug-Ins/Reference4.aaxplugin
C:/Program files(x86)/Common Files/Avid/Audio/Plug-Ins/Reference4.aaxplugin
C:/Program files(x86)/Common Files/Digidesign/DAE/Plug-Ins/Reference4.dmp
/Macintosh HD/Library/Audio/Plug-Ins/Components -> Sonarworks Reference 4 plugin.component
/Macintosh HD/Library/Application Support/Avid/Audio/Plug-Ins/Sonarworks Reference 4 plugin.aaxplugin
/Macintosh HD/Library/Audio/Plug-Ins/VST/Sonarworks Reference 4 plugin.vst
Reference 3 plugins are displayed as "Sonarworks Reference 3".