Cognitive load theory refers to the difference between working memory (short-term) and long-term memory. When we process new information, there are 3 types of cognitive load take places.

The first one is intrinsic. The intrinsic overload relates to complex tasks. It is more challenging than a normal task.
The second one is extraneous. If there is unrelated background music or unnecessary information helps to remember the information.

The last one is germane. It is an ability to connect long-term memory and short-term memory, in other words, when you have base knowledge about that subject it is easier to remember new things.

This theory can relate to when I learn English as a second language. When I remember new vocabulary there are some patterns. If I learn a new word “teacher” I can combine information teach and “er” represents a person. If I have enough knowledge of prefix and suffix. It will be easier to remember the new vocabularies.

Cognitive Load Theory - Psychologist World
It represents the complexity of the task at the same time.

Reference https://www.psychologistworld.com/memory/cognitive-load-theory

It can apply when you teach something new to other people. You need to simplify the step to not to make confuse learners. Waude explains this theory apply when math teacher explains how to use long divisions or Online instructional videos for DIY. The work is broken down into smaller tasks and demonstrated by experts. (Waude, 2017)