For Mac you need to be running High Sierra and Logic Pro X 10.4.2 for all the supported AUv3 goodies. Although it should install the AU when you download from the App Store, running the standalone app is sometimes necessary.
In LPX, you click on the 'MIDI FX' button in the MIDI track and then select Audio Units and Audeonic and then the AU. For some reason LPX shows each AUv3 MIDI effect 8 times, but you can select any of them.
Not sure about Studio One - that may not have AUv3 MIDI effect support.