Telling a story in layman's terms

What are layman's terms? What does that mean? 

According to Cambridge Dictionary it is someone who does not have special knowledge of a subject.

 https://dictionary.cambridge.org/dictionary/learner-english/layman

Can you think of a story or a time when you were giving instructions or a report to your boss and you needed to use layman's terms to get your point across.

Example: I had a water heater installed in my home and the installer/technician explained the way the water heater functioned without getting to technical due to the lack of my knowledge of verbatim/vocabulary I do not use on a daily basis. 

Laymans Terms Technician Technical Terms

Example 2 : When you go to the dentist he or she will explain to you in layman's terms otherwise all of the mumbo jumbo jargon will get you lost. If he told you that you had Gingivitis instead of saying gum disease you might not understand.

Dental-words-vs-layman1 - August 16 2020

Example 3 : To explain layman's terms to you in layman's term is explain it to someone as if they were dumb asses or Forest Gump.