1- QlikViewExpressorDesktopInstaller.exe is used for only Desktop, this does not require license.
2- QlikViewExpressorFullInsataller.exe will install both Standard and Enterprise editions.
The difference between these two Editions consist of multiple components and can be installed in multiple configurations. Both Standard and Enterprise Editions include the Desktop, the Data Processing Engine, and the Repository. All of those components can be installed on a single system.
You may go with Desktop first or as per your business requirement needs.