Lookup Tables (LUTs) are a wonderful feature of most video editing software. They’re sort of like presets that allow you to get a consistent look across multiple clips that when edited together form a sequence. They allow you to remap one set of colours and brightnesses to another.
Generally, there are two different types of LUTs. Corrective LUTs and creative ones. This particular video from Nathaniel Dodson is more about creative LUTs. Looks that you can give to your videos for artistic effect. He shows us two ways to create them using the Infinite Color Panel, as well as manually with adjustment layers.