When you install (in a debian based distribution) the basic texlive it install the compiler -which includes latex, pdflatex, dvips, dvipdf, and many others-, and the basic packages (including classes, styles, etc.).
sudo aptitude install texlive
That is the minimal amount of things should be installed in order to work!
On the other hand if you have HD to spear, you could install the complete set of packages using
sudo aptitude install texlive-full
Editors
There are a huge diversity of editors for writing in LaTeX. Some of them are
- Kile
- Texmaker
- Texshop
- Latexzila, etc
There is also a WYSIWYG editor called LyX.
To install use the command (replace texmaker by the one you want to try)
sudo aptitude install texmaker
Viewer
I usually use the default evince as viewer, but you could try okular, but it will install a huge amount of packages (unless you use KDE environment)
sudo aptitude install okular
texdoc(so:texdoc geometrywill give you the documentation for the geometry package). Usetexdoc texdocto learn more. – jon May 19 '14 at 20:07