The printing process can be summarized in three steps:
3D design. Either start from an existing design in 3 dimensions or software is used to create a model and then saved in STL format.
Parameters. A transition software is used between the design/model and the printer. The software to be used is called Cura and with it you can set the printing parameters (thickness, filling, speed, among others).
Print. The printer executes the code from Cura to generate the 3D model.