Have a look on the RepRap Website and Forum - everything you need to know, and more will be there.
Most 3D printers are controlled using GCode to represent the pattern to be printed. A RAMPS shield is just a convenient way to attach the stepper motor drivers and the mosfets for the heaters to an Arduino Mega.
If you write your own software for the Mega then you can make it do what you want.
If you want to use some of the off-the-shelf software such as Marlin or Repetier then you will need to study how to configure it to match your machine - but configuring that software is not a subject for this Forum.
...R