Welcome to the wonderful world of Slackware.
Once you Slack, you'll never go back.
All joking aside, I started with Slack and it is still my favorite. Once you are at home in Slackware, no other distro can intimidate you.
There is a good Linux primer at about dot com
, though it is Ubuntu-oriented.
Machtelt Garrels has written a fantastic in-depth intro
. I have a printed copy of that on my bookshelf and have read it all the way through.
I also recommend the Slackbook
. It helped me so much that I bought a copy.