Direct Link Rhino 7 & UE 4.27

Hi there, works in editor after I click the direct link button I added to the actor under details. where exactly do I add the -messaging command to supposedly get it to pop up a window to link to in a packaged version.

Do I right click the shortcut, go to properties, then add -messaging under ‘target’ ?

Once it’s been added, in the application, do I have to do anything? hit space bar etc. ?

Thanks