I think so you want to write command in Start >Run.
you can start with this : C:\Program Files\Symantec\Symantec Endpoint Protection Manager\bin\sesm.bat
but if you want to easy way like write only %sep%
Rigth click on he my computer and go to system properties > Advanced> Environment Variables
and
add new variable name sep Value %programfiles%\Symantec\Symantec Endpoint Protection Manager\bin\sesm.bat
and close the window.
after that you can start sep manager with write %sep% to start>run
I hope I understand true.