Creating a new applicationThe first step is to create a new application in the Developer Console. When selecting 'Add new Application' you need to fill in the title of your application and you have two options : "Upload APK" & "Prepare Store Listing". In this case, we select "Upload APK". When we create a new application in the Developer Console we can only upload the .apk file and not both files. Therefore we must first upload the .apk only and afterwards reupload the .apk together with the expansion file (.obb). You can follow this process in the following set of screens. 1/ Upload the application file (.apk) to the Developer Console. After the upload, your screen will look similar to the screenshot below. Here you have the option to switch to "Advanced Mode". Only in advanced mode it is possible to upload the expansion files.
Uploading the .apk and .obb filesOnce you are in Advanced Mode, you will need to reupload the application file. Select 'Upload new APK' -> select the same application file as the once you uploaded before. When the uploading process is complete, you'll notice the application information like the version code, version name & size of the app.
Below that information you get an extra option 'Use Expansion File'. This is where you have to upload the .obb file. Screenshot while uploading.. When everything went fine, the upload screen will look something like the screenshot below. Always make sure you don't upload an expansion file as an expansion patch file, as this will not work with Twixl Publisher. Once you press Publisher Now, the application is ready.