First; find a model!
To print something you require a model (usually this is in STL format, look into websites called Thingiverse and MyMiniFactory for examples). Once you have a model file, you need to make it readable for the printer firmware.
If you can't find suitable model, then you need to design a model yourself (or ask someone to do it for you) or adjust an existing model to suit your needs. "Good (preferably free) Beginner Software for Part Creation?" is a good place to start.
Second; use slicer software
For a printer to be able to print the model, the model needs to be sliced into layers. These layers need to be printed at specific speeds, temperatures, etc. Search online and look at the filament packaging (usually the ideal temperatures are on the packaging) to find the ideal temperature for your filament. If you are not using the right temperatures, your print will most likely fail. Programs that are able to slice models are called slicers. The most popular free (and Windows compatible) slicers are Ultimaker Cura and Slic3r (or its Prusa distribution).
The slicer produces a printer readable file called a G-code file (file filled with printer instructions for e.g. movement and heating). This G-code file can be sent to the printer using specific printer software (e.g. OctoPrint, Repetier-Host, etc.) but more common or simple is to put the G-code file on an SD card and print the file using the print menu on the printer LCD.