Well, in a few words, I can say: launch the program and learn by
using it. It is very simple and full of tips. Most of the buttons
have some tip showing what they will do.

If you have to compile, please read the INSTALL file.
And also, specific libs you have to install (on Debian): 
- libgtk3.0-dev

See also the web site:
http://klavaro.sourceforge.net


- COLORS

Some colors may be configured through the file preferences.ini 
There you should create a session named [colors] and set some colors
with the internet/html syntax (#RRGGBB). Example:

[colors]
key_fg=#332200
key_1=#112233
key_9=#213243
text_intro_fg=#222222
char_untouched_bg=#fffaf8
char_wrong_fg=#880000
char_correct_fg=#009900
char_retouched_fg=#bbbbaa
cursor_blink_bg=#ff88ff

The preferences.ini file holds all the default key/value pairs, since the first time when
 the application is run. But they are never overwritten after that, so direct edition should
 be done by the user to change the colors.

Here is the complete list of keywords to set colors:

Background and foreground for the tutor introductory texts:
text_intro_bg
text_intro_fg

Background and foreground for the tutor texts before they be typed out:
char_untouched_bg
char_untouched_fg 

The same for the tutor texts after they be correcty typed out:
char_correct_bg 
char_correct_fg 

Same for tutor texts after they be wrongly typed:
char_wrong_bg
char_wrong_fg

Same for tutor texts after they be correcty retyped, correcting errors (only in fluidity module):
char_retouched_bg
char_retouched_fg 

Blinking color of the block cursor in the tutor tests:
cursor_blink_bg
cursor_blink_fg

Foreground of keys in the virtual keyboard:
key_fg

Background of keys, according to the finger responsible for it, from left to right (key_5 is valid 
 for both thumbs, it is the space key):
key_1
key_2
key_3
key_4
key_5
key_6
key_7
key_8
key_9


- GOALS

And also, the goals for touch typing skill may be configured in preferences.ini file. They give the 
 limits for each tutor module, so the user is told when he/she should go to the next level. They also
 appear as horizontal lines in the progress charts.
The default key/value pairs used in the application show up after the first time one runs and close 
 it gracefully, take a look at your preferences.ini file.

- LEVELS

These are similar to the goals above, but they are used only to distinguish the comments done by the
 tutor after each practicing session, along all the modules. With them, the program knows how the user
 is doing with his training, and then suggests more directions to take. As with GOALS, see your
 preferences.ini file, after launching and using the application for at least one time.