Cubase 11 is only a couple of weeks old so there probably won't be any specific books yet that are totally up to date. Mind you, the main bulk of the software hasn't changed too much in the past couple of years since Cubase 10 (although there are many great new features in both C10.5 and C11, but they are mainly enhancements to what has gone before). A book or online course designed for C10 or 10.5 should cover most of the modern package.
Steinberg have a very useful Cubase YouTube channel which is full of tutorials and video tips. It's a great source of information.https://www.youtube.com/c/Cubase/videos
It's worth noting that when you're actually sat in front of Cubase, the help menus and the manual within the program require you to be online to view them at their best. I usually download a .pdf of the manual (you can do this for free on the Steinberg website even before you buy or download the software) and put it on a memory stick so I can refer to it without having to turn Cubase on or have the music computer online, hogging resources. or I can read it on a laptop or tablet
You dont mention budget for the monitors and headphones. There's lots of choice at all price points. As others have said, a lot will depend on the space you/they have available for music making and how you can utilize it. In a "smallish square-ish spare room" type setup I'd perhaps look at prioritising some decent headphones over spending lots on monitor spakers. If the space is a bit larger and can be set up so it behaves nicely acoustically, then It's worth spending a little more on monitor speakers.
Handy guide to headphones:https://www.soundonsound.com/reviews/headphones-studio
(I use the Beyerdynamic D770 ones mentioned and am happy, I've used the Sennheiser ones also mentioned in the article that others have mentioned above and was just as happy. Other folk will doubtless have their own opinions.)
With monitors it's harder to recommend something without knowing a bit about the space they're going to be used in - I'd maybe look on a well stocked web retailer's site like Thomann or Gear4Music and see what's available in your price range - Manufacturers like Adam, KRK, Yamaha etc. all do a range to suit various budgets and uses.
A book that covers all sorts of things to do with setting up a home studio system, including chapters on room acoustics, mics, monitors, headphones etc which I've found very useful is "The Producer's Manual" by Paul White. Whilst the recording and mixing sections aren't specific to Cubase, the principles discussed are easily adaptable to making music in the modern Cubase environment. There's a whole heap of valuable stuff in there! https://www.soundonsound.com/shop/books ... ers-manual