How to create API access to Google Play Console

How to set up an API access or service account for Google Play Console? Applications like https://appstoremanager.net (just our example here, other applications are similar) require technical access to Google Play Console for their tasks (e.g., upload of app icons, feature graphics, screenshots, descriptions, etc.). This tutorial describes the main steps of the setup. What to do in Google Play and Google Cloud Console and how to get the JSON or P12 key file. In addition, how to configure specific access rights.