When you clone this repo, youd find entry poin to be index.mjs. However after starting the server with index. mjs and having access to the resolver and schema files imported into it. You can then change the entry point to server.js to run the resolver and schema embedded in(not imported) in the server.js file.
The purpose of adding the 2 servers in one project is to make it quick and easily accessible as well as give the user 2 options to choose from. This means, as soon as you clone this repo, youd learn 2 different ways you can run a graphQL server.
Happy coding