Step 1: Get a 3D Model
Now you really have two options here, you can design your own 3D model using a computer aided design (CAD) program. Or you can just download a model someone else made and published online.
Step 2: Slice the model
In order for your 3D printer to create your object it needs to be sliced up into layers and converted into Gcode. Gcode is the step by step instructions sent to your printer.
Step 3: Print the model
Time for the fun part, always remember that the hot parts of the printer are not to be touched especially while it's printing.