Besides Dan Kreider’s book (which I find especially good for leading the user into “thinking Dorico’s way” rather than holding on to assumptions from other music software) I have also found Daniel Spreadbury’s tutorial “Typesetting Choral Preces and Responses in Dorico” exceedingly helpful, after a week or two of familiarizing oneself with the basics and gaining a little fluency. It really does walk the user step by step through creating a multi-page piece of the type described, including the layout issues. Even though I’m never going to need an evensong service, following all its steps gave me a big step forward in understanding.
Are there other similarly detailed tutorials available? (Darren Jones’s book has two, I know, though they’re on more of a beginner’s level than this.)