I have a German keyboard; but I use the English version of Dorico.
I understand that the letters Z and X are used for Zoom in and out resp, and these work for me, though they are more memorable on the UK/US keyboard layouts. When I click on the View menu, CTL + = and CTL + - are given for these, and they also work. Clicking on “help” brings up a keyboard layout in a browser window. On this it says that Zoom in can be done by CTL + NUMBERPAD =
The problem is that there is no NUMBERPAD = on my keyboard, or on the drawing on the webpage. What is referred to is NUMBERPAD - (top RH corner of the numberpad) which does the same as CTL + (normal) - (i.e. Zoom out)
I have the same problem if I change my keyboard layout to EN. There is only one way to zoom in.
Some numeric keypads have a split key in the top right-hand corner, in which case there will be both a - and a + key there, but typically on Windows this is a single key (we Mac users get two keys there, assuming we have a numeric keypad there at all). As Leif rightly points out, though, you can define your own key commands, so you shouldn’t be stuck.
I tried to be clear, but obviously was not clear enough. The intention of my posting was to point out that, unlike the claim of the instructions on the help page with the keyboard layouts, there is no = key on the numberpad. See attacheded screenshot.