There are an absolute glut of LaTeX tutorials out there to get you started. Here's one:
http://www.andy-roberts.net/misc/latex/index.html
But there are many, many others. Some are particularly good for people in certain specialties. For instance, here's an excellent LaTeX resource for logicians:
http://www.phil.cam.ac.uk/teaching_staff/Smith/logicmatters/...
If you're comfortable with Vim or Emacs, both of them have good LaTeX support. The AucTeX package for Emacs is particularly excellent (it needs to be installed separately, but Debian packages it).
There are also editors best described as "LaTeX IDEs". They provide a syntax-highlighting editor and have particular support for running the LaTeX processing toolchain, parsing error messages and warnings (a nontrivial proposition), and sometimes provide support for generating LaTeX code snippets like table layouts. One such package is Texmaker, a Qt-based IDE with a look-and-feel somewhat like Qt Creator.
http://packages.debian.org/search?keywords=gedit-latex-plugi...