Yum is installed (originally) more or less like any other rpm you add to an existing system. After downloading one of the rpm's above you simply:
rpm -Uvh yum.X.rpm
where X is, of course, the revision number you downloaded. Do this initially on the server(s) you wish to use as yum repositories and perhaps a single test client only. If this install fails, be sure that yum's dependencies are satisfied on your system. As of right now its dependency list reads something like:
rgb@lilith|T:167>rpm -qR yum
/bin/sh
/bin/sh
/bin/sh
/sbin/chkconfig
/sbin/service
/usr/bin/python
config(yum) = 1.97-20030522
python
rpm-python >= 4.2
rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
It is beyond the scope of this HOWTO to describe how to set up any of the servers that can be used as vehicles for a yum repository. Fortunately, documentation for setting up an FTP or HTTP server on a linux (or general Unix) server exists in abundance. Interested novices are referred to The Linux Documentation Project website, where one can find HOWTO's (like this one), FAQ's, and outright books on doing nearly anything complex on a linux system. Your favorite technical bookstore is likely to have good books on at least the more important tools (such as apache).
For our purposes here, we will assume that you already have a functional HTTP or FTP server that you wish to make into a repository. It will need good bandwidth to all the clients you wish it to serve. It may need mechanisms to be in place to restrict access to the server to a local domain, or you may be comfortable permitting the server to be used by outsiders. It should be very strictly controlled in terms of access and security as it is an obvious target for crackers seeking to take over an entire network by slipping a malware rpm onto your repository for "automated update" to an entire network at once.
A double-barrelled shotgun behind the server room door, loaded with salt and tacks, is not out of the question.
With this given, we will now present instructions for setting up an rpm repository and preparing it so that yum clients can use it for all of their operations.