There's literally dozens of /r/ELI5 threads on this[1] that are useful:

- https://www.reddit.com/r/explainlikeimfive/comments/23ubdy/e...

- https://www.reddit.com/r/explainlikeimfive/comments/3az0fa/e...

[1]: https://www.google.com/search?q=eli5+tpp