Remember that in order to include the P5.play library you need to include the source code in your HTML file. This will tell P5 where to compile the source code from. If the P5 web editor was the brain, adding this library would be like adding a new part part that brain that can perform unique tasks.
Be sure to include this line in the body of your HTML file in order to include the P5.play library.
The Resource material for the P5.play library is available here. A downloadable version of the library’s code can also be downloaded from this cite and uploaded into whatever code editor you are using, even if it is not P5.
Examples using the P5.play library’s various sprite and animation capabilities are available here.
Allison Parrish’s Lessons on P5.play.