simple Drupal 8 custom module

I need a drupal 8 custom module, named for example "invoices", to show a list of documents, like Pdf or Excel files. This is the scenario: I've a role named "customers" and a structure of filesystem as following: -- user1 (directory) -- [login to view URL] -- [login to view URL] -- [login to view URL] -- [login to view URL] -- ... -- user2 (directory) -- [login to view URL] -- [login to view URL] -- [login to view URL] -- [login to view URL] -- ... -- user3 (directory) -- ... where user1, user2, user3... are drupal users with the role "customers". The module should add a route like 'user/{user}/invoices' (only for the role "customers"), to read the user directory and show the list of included files: -- [login to view URL] -- [login to view URL] -- [login to view URL] -- [login to view URL] -- ... Also, the module should add a Tab in the account page. No Css style is required. This is a very small task of a big project, but I want to use this simple activity to meet valid drupal developers and hire them for other tasks. the budget is 40$