You have to look for a user guide, typically found in the installation directory, because the new developers that acquired this software don't provide anything about it (technical documentation, user guides, readme files, etc).
Also, as far as I know for these applications, you should be able to select a new source if there is a setting for that. The new device/camera needs to be installed as well and compatible with the software to be able to select it in the menu mentioned earlier.
