Fantasy Football for chat app

I need to integrate a Fantasy Football game into my existing friends and family chat app.
The developer for this job will need to create VB.Net (VS 2012 or VS 2019) project using http GET / POST using an existing API like Yahoo Fantasy Football API.
The VB.Net app needs to comprehensively have all the API’s functionality, from creating a league/joining a league to the end of who won/lost.
The developer needs to explain the process of the finished app so that we are able to integrate that app into our existing chat app.