Loads of questions on setting up ESLint and Prettier for different IDEs

Theo's recent video about Prettier promted me to look into eslint and prettier and make sure it's set up the right way in our monorepo. I've also watched the talk from Josh Goldberg, but I'm very very confused about how to set it all up. I've shared a file with my team-mates to resolve some my confusion and to come up with solution and a .md file for our docs to explain how linting is implemented in our codebase and how to use it with VSCode or Webstorm. I wanted to share an image of said file here. Hoping that you might be able to provide clarity on some of the questions and WTF moments described in there: