[ubuntu] Installed minimal Ubuntu, now what?

I went with the install of minimal Ubuntu rather than trying to remove stuff from a full version per my recent thread. When I got to the option for software selection, I only chose the first program which was basic Ubuntu server or some such. After that I get the terminal like screen that I can log into, the only thing is, once logged in I have no idea what to do or where to go. I tried apt-get of firefox but it wouldn't let me.

Please tell me what I need to do to start using minimal.