How do I make Dorico show the names of instruments in an alternate layout?
I have written a duet and now made a layout with the two Alto Saxes. But the instruments names/staff labels are not shown.
How do I make Dorico show them?
Staff labels are determined by Layout options, which are layout dependant. Make sure you select the accurate layoits in the right panel of Layout options, then choose the right options for your labels.
Thank you. Been looking for that for 20 min.
Sometimes you just can’t see the forest for the trees. 
If you were searching the manual, can you let me know what you were searching? For instance, “show instrument names” for me brings up the relevant topic on the first page.
Is there a difference between the manual and the help page?
Because I searched the help page first and I found many articles explaining how it works, but not how to use it.
The online help is the manual yes, it’s available as both a PDF and webhelp.
Steinberg manuals are all segmented - tasks (that describe what to do to achieve a specific result) contain only the necessary information for that operation; more explanatory information is on a separate page. Given that for most notations/concepts, there are plenty of different things you can do with them, that makes sense.
So if you search “show instrument names”, the 2nd result is the introduction to staff labels. This both gives you information about when/how instrument names are used to the left of systems and confirms that the term for when instrument names appear to the left of the systemic barline is “staff label”. Now really, there should be a related link on that page to hiding/showing staff labels (I’ve made a note to add that) because that’s probably one of the most common things people want to do with staff labels, although not the only thing. In general though, if you’re looking for instructions for how to do something, the relevant page will have an active verb: “hiding/showing” or “moving” or “inputting” etc. “Hiding/Showing staff labels” was the 6th result, first page, when I searched “show instrument names” and the preview of the beginning of the topic shows the introduction to that topic so you can gauge from the search results page whether that page is likely to be what you’re looking for.
Oki. I just made the exact same search you described: “show instrument names”.
2nd search result for me was “changing the text shown in percussion legend”.
But the 6th result was “instrument names in staff labels”. And it is also described how you access the function.
So maybe I have to work on my patience. It’s the reading part that irritates me. A picture or pictures says a thousand words and maybe I have gotton a little used to Ikea level manuals. 
I will try to search with more patience. Thank you.
The Dorico manual already has quite a large number of images compared to other Steinberg manuals, I believe - I tend to put in quite a few, especially for tasks that include a this-or-that choice so you can see a before/after or this/that comparison.
Producing screenshots, adding them to the text, and then maintaining them as the software updates (particularly for screenshots involving the UI itself) is a hefty job, so I wouldn’t hold out for pictures accompanying every step for every topic in the manual any time soon!