There is one missing ingredient -- yes you can use the CD1 to get a base install that has network support, but your usual Mandrake tools won't know who to call to get the rest, and for that you must update your urpmi sources.
This is no trivial task -- the list of mirror sites changes like the wind and for that reason you need to know about
Easy URPMI where you can pick your mirrors for various parts of Mandrake (updates, contrib and especially for Main) -- Easy URPMI will give you the command lines to set up your sources, but watch the output carefully because the sources you select may be offline, temporarily busy, or just plain broken.
Once you've set your URPMI sources, then yes, you ask for any package by any substring of it's name, and all associated packages will be downloaded and installed, and you can use the usual GUI tools to do security and update package management.