If Studio One Professional does not show the Edit with VocALign command in its Audio menu after installing VocAlign Ultra, please update to Studio One version 5.1.2.62686.
The Edit with VocALign command willl appear in the Audio menu and VocALign Ultra will respond to it.
If you are using an earlier version of Studio One Professional you can still use VocAlign Ultra as an ARA plug-in: hold down the Option key on your computer keyboard and drag the VocAlign Ultra VST plug-in from the Effects Browser onto the selected Audio Events you want to align - Guide and Dub(s).
This will add VocAlign Ultra VST3 (ARA) plugin to the selected Audio Events, and open the VocAlign Ultra interface in the Studio One Edit panel.