Understanding font-lock

[Heime]

I am finding the use of font-lock too complicated.  When I make a new buffer 
and apply `text-mode` or `org-mode`, `font-lock` in enabled and can print text 
with colour using `font-lock-face`.

But when I do not set the mode of the buffer, I get `fundamental-mode` 
automatically.  What should I use to print in a new buffer? 

Cannot really understand what `font-lock` is about.  Does it have to be enabled 
to print in colour?