If you have problems understanding what *any* thing means, just ask. It will be answered politely, instead of frustrating everyone when someone asking for help does so by "Something doesn't work, help me!" (just speaking generally now).
It makes it easier for those who help to know if the user knows what prepending "sudo" to a command does... but enough of that, let's give some help.
You can open any program in the terminal just by typing it's name (for example firefox). nano is Ubuntu's standard command line text editor, gedit is the standard graphical text editor. If you like gedit more, you can either open it by clicking on Applications -> Accessoires -> Text editor or by just typing gedit into a terminal. This way, you can open the modules file by ``` gksudo gedit /etc/modprobe.d/options
According to the HowTo cyberdork linked to, you should now just make a new line (for example at the bottom) and add this to it:
options snd-hda-intel model=imac24
If you prefer a simple alsamixer GUI, just type this into a terminal (and ask if you don't understand what the command means **)
sudo aptitude install alsamixergui
The same can be accomplished by clicking on System -> Administration -> Synaptic Package Manager and there Search -> "alsamixergui" -> right click -> Mark for installation -> Apply
It's just that in this case, doing it with the terminal is much, much faster.
You can then open the program either in Applications -> Sound&Video -> alsamixergui ... or just type the name into a terminal ;)
The command **lspci** will list the devices connected to the PCI interfaces of your mainboard, which I asked you to issue in order to see what audio hardware you have.
** We had cases here where people disguised commands to delete all the users files as "help", if executed blindly without understanding. You should at least have some basic idea what a command you found on the internet does.