This is downloading a zipped file that is supposed to make your wireless work. wget is the download program, followed by the web address, followed by the name of the file you are down loading.
This command is unzipping the file you just down loaded. In linux we use tar (amongst other things) insread of zip.
tar -xvf madwifi-hal-0.10.5.6-r3835-20080801.tar.gz
This bit moves you into the unzipped folder, just like clicking on an .exe
Now you are installing software that allows you to to configure and install programs from the original code.
sudo apt-get install build-essential linux-headers-$(uname -r)
Theses 2 commands are installing software on your system a bit like following a set up wizard.
Sorry if I`m being too basic.
Are you getting any errors.
You need an internet connection to download the 2 packages, so plug your laptop in.
After you`ve completed the steps you may need to reboot.