This article explains in-depth everything about selectors in Minecraft. Selectors allow you to target any entity in the game, whether it be from its name or type or anything else.
This article explains in-depth everything about XYZ coordinates in Minecraft. XYZ coordinates allow you to pinpoint any location in the infinite Minecraft world.
This article explains in-depth everything about the give function in generators. This allows you to generate complex give commands that normally would take months to type out. I might make the 2nd part to this sometime in the future covering the summon function.
Java Coding Class: Generators Tutorial