Hello, Linux n00b here. I need a little help understanding the package system. How do I update my packages? How do I install software Ive downloaded for my Slackware linux ?

http://www.slackware.com/config/packages.php

You can get a lot of extra packages here:
http://www.linuxpackages.net/

Slackware uses two pretty good package managers. Slapt-get and swaret. Both of which can be installed from www.linuxpackages.net

hello : )
there are two basic ways to install software in Slackware. (1) Installing from Slackware software packages (2) installing from source
(1) It is the simplest way to install any package. go to www.linuxpackages.net and search any software you need, download it and put it in say, your home directory. in command prompt go to your home directory (just type cd and enter, that'll take you to your home) and as super user (root) type installpkg <packagename>.tgz. that's it! all Slackware package ends with *.tgz and you need one line command to install them, but somebody has to prepare a slackware package to be used with installpkg.
(2) these are not customized for slackware but they are source. to install a software from source:
(a) unzip the source and go into the unzipped directory
(b) ./configure
(c) make
(d) as super suer (type su and give root passwd) make install
if the ./configure fails, check what went wrong, go to linuzpackages.net, download the missing package, install it with installpkg, do ./configure again.

this is a very nutshell description what you should do to install a package. for readymade package you can go to linuxpackages.net and also to www.slacky.it

Thx for the replys. I think I understand everything a little bit better.