cant install license server

Here is a "Customer Support Guide":
https://www.ptc.com/en/support/csguide/Licensing/Modify_License_Configuration 
https://support.ptc.com/appserver/cs/lm/index.jsp 

Commercial license or student license?

Floating license or node-locked?

The license manager install is an option on the PTC Solution Installer program menu.

One thing to add to the other suggestions.

In older versions of Creo the license server was "bundled" in with the Creo installation software. This was kind of a pain if all you wanted to install the license server.

The current setup is that you download the license installer as a separate package.

If you're used to the old way of doing things, it's confusing to start up the installer and not see the option to install the license, at least it was for me.