Sorry for being a pain. I now have a couple of AAT instances which is great, following your intructions.
I've done exactly the same with another, but the getting the below just after typing node install:
error [09 Nov 20 17:07:27 +00:00] Server selection timed out after 30000 ms
error [09 Nov 20 17:07:27 +00:00] failed to set app.db
Thanks as always.