Where can I find the Documentation for Ubuntu's Default LibreOffice

I’m not adapting well to the new LibreOffice GUI. Not because it is gray or because the icons have changed, but manly because there are no more Font options in Impress’s toolbar, and because it looks nothing like the screenshots on the manual (at least not the “Getting Started with LibreOffice 5.1” guide) or most help pages online. The Help does not really address this paradigm change if you look for “Font”.
Screenshot of what It looks like:

Is there a document that addresses this new GUI, so I can look it up before asking questions here and actually find out how to make good use of it by changing my work habits?
I tried view>toolbar>text formatting, and it does add a tiny section to the toolbar, which I can expand to include Font selection. Still some documentation on how to work without having to add a whole new toolbar layer would be nice.

You activate (menu View) the toolbar Text formatting. It only appears if text is selected (context sensitive). You have mentioned that. (Additional to that you may have a view on the sidebar also when text is selected.)
A right-click on the toolbar (Customize toolbar) may help you to show all the elements you would like to work with. Or you find the arrows at the end of the toolbar to enlarge it and to select the wanted elements for permanently be shown.
In my opinion there is no change in the behaviour of impress; the only thing is that the Text formatting toolbar is not natively shown and you have to activate it if wanted.
The look of the toolbar(s) easily can be changed if you choose and install by your package manager, on my linux it is Synaptic. Look for libreoffice-style-xxx (xxx stands for some different additional symbol styles).

Still some documentation on how to work without having to add a whole new toolbar layer would be nice.

In my opinion you don’t have to add a new toolbar, only to activate and customize the existing one.

Any more questions?

That helps, thank you, so there is no illustrated User’s Guide that present’s LibreOffice’s current GUI? If this doesn’t exist, what ‘xxx’ in libreoffice-style-xxx would change it back to what it looks like on the most recent User’s Guide? The text based help is not the best place to learn a new GUI. I really have nothing against the new GUI except for the fact that it is not presented to the UG’s readers.

Hello @Benari,

To get the Font Options in your Impress toolbar, check the menu "View : Toolbars : Text Formatting". You can drag the toolbar at its handle to a new row.

To get some documentation about a topic in LibreOffice, start at the Help files ( press F1 ).