The following skills are expected from the reader:
Basic UNIX commands: see http://tille.xalasys.com/training/tldp/.
Experience as a system administrator: use commands described in above resource a lot in a lot of different circumstances.
Familiarity with the common Internet protocols, such as HTTP, IMAP, POP, SMTP, LDAP: read a couple of RFCs or get friends with the man pages of your favorite daemons. If you really don't know where to start, man 7 ip is always a good one.
Furthermore, this document assumes that you currently have a directory server configured and running. If you want to know how to set one up, try the following:
Ask your service provider how they did it, or
Refer to the Sun docs about Directory Servers (note that they're all more or less the same, except for the names marketing comes up with for every new sub-release), or
Read the docs that come with your Linux distribution and OpenLDAP package, or
Read the LDAP and/or LDAP Implementation HOwTO.