MAS: Registering a new app on the MAS
You have to register a new application before being able to upload your binary.
In the Member Center, create a new app ID (app IDs are managed on the same screen that the certificates are):
Then, connect to the iTunes Connect platform:
In the My apps panel, create a new app:
This will create a new, empty app where you can fill all your data (screenshots, description, etc).