You could try by typing "startx" once you've logged in. I am assuming that you made a full installation as well, or you may not have x-server installed.
I probably will get flamed by saying this(because most Slackware users believe that Slackware is the best thing since sliced bread), but you are apparently far too new to Linux. If I were you, I'd start with another distribution, such as Ubuntu (which has the casual/end/new-user in mind), to make it easier for you. If you did not know how to get into the gui, you most likely will get to frustrated with Linux and quit even before start using it.
Just a tip.
Last edited by Mega Man X; 10-10-2007 at 04:02 PM.