The usage of a proper code editor is key to every development project.
Atom is a simple and straight-forward editor that excels though its ability to be extend with many packages.
A short tutorial on the various functionalities can be found here.
An older video from LearnCode.academy is available here.
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Fork or download the IAD P5.js template here. From the Webstorm File menu, select Open and navigate to the P5js_Standard directory and open.
From the project screen, select Webstorm->Preferences in the menu bar.
Select Download, wait for the available libraries to load, then search for P5 and click Download and Install. Ensure type/p5 has a tick for enabled, and click apply.