Dorico – No Sound – Dorico

I’m new to Dorico (and Steinberg) and a fairly well-rounded notation software user (MuseScore, Sibelius…and Notator) but am stumped with no sound being produced when simply trying to play back a demo.
I’ve watched the youtube video (watch?v=5BcPJd92zqU) that seemed promising, especially at about the four minute mark where there was an obvious difference between Anthony’s hitting the virtual keys on the virtual keyboard producing both sound and visual cues where I could only see the keys “moving” with no reaction on the MIDI light or level meter at the top of the window. I was disappointed when, after his “keep watching” message at about 4:50, he didn’t address what to do in the event that the Halion sounds are present but simply not responding. I’ve run Dorico completely solo after rebooting, but do still have sound when re-testing with other software, including YouTube of course.
I’m running Dorico SE 3.5 (to test it out) on a Windows Surface Pro X with 64 bit ARM processor, if that makes any difference.
I don’t think I’ve wandered off the path laid out by the instructions I’ve read and watched in my hour-long experience so far and would be grateful for any help with getting sound out of the software.