Log in to Ambari.

Browse to Admin > Stack and Versions.

Click on the Versions tab. You will see the version currently running. The full version is dependent on the HDP version you are actually running. For example, if you are currently running a maintenance release of HDP 2.2, you would see something like HDP-2.2.0.0-2041.

Click Manage Versions.

Proceed to register a new version by clicking + Register Version.

Select the HDP 2.3 Stack and enter a two-digit version number. For example, enter 0.0(which makes the version name HDP-2.3.0.0).

Select one or more OS families and enter the repository Base URLs.

To copy a Base URL for a specific OS family, see the list of available HDP Repositories.

Click Save.

You can click Install on..., or you can browse back to Admin > Stack and Versions. You will see the version currently running HDP-2.2.x.y and the version you just registered HDP-2.3.0.0.

Proceed to Installing a New Version.