In response to your second question, I assume that you would like to launch a graphical desktop environment, rather than using Slackware in text mode at the console.
Providing you've installed X and it's configured, just type
startx at the command prompt, and the default graphical environment should be launched (KDE 3.1 on my Slack 9.1. box). You may need to edit your $HOME/.xinitrc file to launch the window manager of your choice.
Other than that, more info is required, please elaborate!
Cheers
ZB
http://www.zazzybob.com