To update the build for an existing app, go to the app's manage page.
When you upload a binary via the upload page, it creates a new app record identified by a publicKey. Each publicKey is treated separately and has its own link, and you will see each new app appear on your dashboard.
If you wish to update the build for an existing app, go to the app's manage page and you will see an option to upload a new build. Uploading a new build will update the binary for that publicKey and not create a new app record.
For accounts that have a launch page, the launch page is configured to a specific set of apps identified by their publicKeys. If you wish to use a new build for the launch page, please upload a new build for that app instead of uploading a new app.