I do not care if I did the set wrong.
Then you are a fool.
Percent signs are used to indicate expandable tokens to the command interpreter such as..
Variables
set var=rasputin
echo %var%
Metavariables used by FOR
FOR %%A in (A B C D) DO echo %%A
Passed parameters
@echo off
echo parameter 1 is %1
echo parameter 2 is %2
echo all parameters %*
The name of a batch script
echo this batch file is %0