Copy the AU component to  /Library/Audio/Plug-Ins/Components
OR
Copy the VST plug-in to  /Library/Audio/Plug-Ins/VST
OR
Copy the VST3 plug-in to  /Library/Audio/Plug-Ins/VST3  (create the VST3 folder if it is absent) 

If MacOS informs you that the MathAudio plug-in cannot be opened because the developer cannot be identified, do the following:
1. On Finder, click Go.
2. Select Utilities.
3. Double-click Terminal.
4. Type the following command: sudo spctl --master-disable
5. Hit Return.
6. Authenticate with an admin password.
7. Hit Return.
8. Exit Terminal.