When you first log in to the app, you will be prompted to link your social media accounts. When you tap on Facebook, you will be taken to the Facebook app and the app will ask to access pages you manage.
This allows the Players' Post app to post to your athlete page at the push of a button. When you tap on the Twitter and Instagram icons, you will be asked to log in to your accounts in order to set-up the connection.
Linking your social media accounts is a one-off process that you will not have to do again.