Well configuring apache is really not distro specific, some might place the root docs in different places and other small tidbits, etc, but I don't know of any specific docs that pertain to Slackware.
You can get the Slackware packages from any slackware mirror, which makes it easy to upgrade and install apache, places all the files in the correct location, won't overwrite any existing files (but always good to back up just in case) and so on..
The conf files are always located in:
Alot of the commands used are in /usr/bin, /usr/sbin or /sbin... like apachectl, etc.
But to get a grasp on apache, I'd suggest just picking up a book on it for a hard copy or just visit their page where they have their own docs. www.apache.org