Finding packages to install
How did you learn about the package?
If the information came from these FAQs, you should already
have a link to the file (there are lists at the end of each answer):
click on one of the links associated with the package, and you can
get the package (which may be one file or several).
If you heard about the file somewhere else, it’s possible that the
source told you where to look; if not, try the CTAN searching
facilities, such as http://www.tex.ac.uk/search/. That (rather
simple) search engine can return data from a search of the CTAN
catalogue (which covers most useful packages), or data from a search
of the names of files on the archive.
Packages come in a variety of different styles of distribution; the
very simplest will actually offer just package.sty — in this
case, just download the file and
get on with installation.
Normally, though, you will want foo.sty but that file is distributed
in a LaTeX documented source file foo.dtx; thus you should
search just for foo — foo.sty won’t be visible
anywhere on the archive or in the catalogue.
Since most packages are distributed in this
.dtx
/.ins
way, they usually occupy their own
directory on the archive. Even if that directory contains other
packages, you should download everything in the directory: as often as
not, packages grouped in this way depend on each other, so that you
really need the other ones.
Having acquired the package distribution,
“unpacking LaTeX packages” outlines
your next step.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=install-find