In {Home}.TeXmacs/progs/ or any subdirectory of it. Both files should be in the same subdirectory, since vi.scm is loading normal.scm with (load "normal.scm")
.
Moreover, if you put the files in a subdirectory of {Home}.TeXmacs/progs/, you have to modify the first line of vi.scm by adding the name of the subdirectory in the texmacs-module
command: for example, if you put the files in {Home}.TeXmacs/progs/vi-mode, then the first line will be
(texmacs-module (vi-mode vi)
;; (:use (generic generic-kbd)
)
Once that you have the files in the directory where you want them to be, you have to load them from your TeXmacs document. The way to do this is through the use-module
macro, that you can for example put in your preamble (Menu Document->Part->Create Preamble)
Using again the same directories as in the example above, you would need the following
<use-module|(vi-mode vi)>
which you enter starting with a backslash (then the rest should be intuitive, use return to activate the macro once that you have typed \use-module, then an area for the argument will appear and you will be able to use the cursor to move to the argument area).
After that, I tested just a bit. As far as I understood, use esc to start vi mode, and o to exit when in the command mode of the vi mode.
Hopefully @susoren (or someone else who played with/used this mode) is still around to tell you more.
I did not understand this question, sorry. As far as I know on a German keyboard [ is AltGr + 8
And for your point 3, you need someone that uses a Mac keyboard.
If anything is not clear on how you make the files available to TeXmacs and load them in your document just ask.
The manuals for TeXmacs are at http://www.texmacs.org/tmweb/documents/manuals/texmacs-manual.en.pdf (the general manual) and (for the manual where the use of Scheme is documented
in details) http://www.texmacs.org/tmweb/documents/manuals/texmacs-scheme.en.pdf but they can be overwhelming especially as a first-time user.
G.