Respectively, "whatis" provides a one-line description of a command, "man -k [keyword]" finds all instances of [keyword] in the manual pages, and "locate [fname]" shows you where [fname] is in the directory structure.
A cron (UNIX scheduler program) task needs to be run to create these databases. Unfortunately, it won't run until the end of the first week, assuming you leave your machine on the whole time.
You can force an immediate update, though, by following these steps from a terminal session:
su root
cd /usr/libexec
./makewhatis {-- takes a few seconds to run --}
./locate.updatedb {-- takes up to a few minutes to run --}
exit
The above commands will now work as expected.

