Yum- how to do anything?

[Al]

Many thanks to everyone who answered my install problem query earlier 
this month. I managed to install using the manual method, installing 
gnome rather than KDE as it was elements of KDE that the auto install 
failed.

Now that I am up and running I would like to install more software BUT 
despite reading all I can (Yum help is hilariously bad-its like the 
cryptic crossword!) I always get no further than the same error message 
whether I try to install, info or list. Essentially I want to install 
from the CD's but yum appears to be trying to access a YDL web address. 
How do I tell it to look at the cd-rom?
Secondly, how can I see what packages are available on the CD's and what 
they do? If I can find what I am looking for, can you give me an example 
of EXACTLY what I should type, spaces, underscore, etc., for example, 
yum install kde    ?

Incidentally I also tried using apt-get but received a reply telling me 
that there were no apt available files on any of the CD's.

Clearly. I am missing something, I would be grateful if anyone could 
tell me what it is.

Al.