Installation manual for arcgisdesktop versions 10.1 to 10.x for concurrent use licenses.
If you already have a version 10.1 - 10.x installed and want to update, you only need to run the installer over the previous version, no need to uninstall!
License authorization video tutorial created by Brittany Yu from Esri Canada (audio in English):
Authorizing an ArcGIS Desktop Concurrent Use License (Online) - YouTube