Okay, you've installed your Linux OS of choice (Kubuntu, Kubuntu, Kubuntu) and love the way it looks and operates. It's fast, looks cool, and has lots of cool programs on it. Now you are ready to venture out and install your own programs. You've probably noticed by now that Linux may look like Windows but it is definitely not the same. Just forget what you know about Windows for now and pretend you are looking at a computer for the first time. There...That's better.
You've also probably heard about "the shell". What the heck is shell? Why are all these people in the user forums talking about typing a command like "fdisk -l" in the shell? Where the heck is the shell? Where are they typing all this crap????? Ahhhhh!!!!!
Calm down. It's okay. Remember back in your Windows days where you could select Start, Run, then type "cmd" and a black screen would pop up (DOS)? Well, that is what the shell is in Linux. It's the window into your operating system without the nice GUI (Graphical User Interface) on top. There are a lot of Linux and DOS boxes running in this world without a GUI. It's all command line / shell interface. It's good for servers and such but not so good for creating office documents or spread sheets.
So...first things first. Learn about the shell because you will want to use it. Follow this link and read it from end to end. http://www.linuxcommand.org/learning_the_shell.php Bookmark it for future reference.
Finding your shell interface is quite easy but it depends on the version of Linux you are using. In Kubuntu, it is the black icon in the system tray at the bottom of the screen. You can also select "K" (the start button) then "Shell".