Start LinuxCNC by choosing Applications > CNC > LinuxCNC from the menu, or by typing "linuxcnc" at a command prompt.
You immediately see the configuration wizard which shows a list of available sample configurations. By clicking on each you can read about it. When you are ready, you can run an existing configuration or you can copy an existing configuration directory into your own directory (~/linuxcnc/configs/) to further customize it. Next, you may wish to read up on Configuring LinuxCNC