We need your account info and an Android/GSF ID to simulate the download request and send it to Google Play Store's Server.
1
Prepare an Android device
with Google Play app installed (or you won't be able to download apps). If you don't have any devices meet that the requirement,
email me.
2
Install
Device ID (
mirror) on that Android device. This app will show necessary information for you to use on APK Downloader.
3
Log in to APK Downloader using the information showed in Device ID app.