I know this sounds so stupid and lame but I'm a noob at mIRC so idk. what is it and how do I access it?

It is wherever you installed mIRC. By default, it's c:\program files\mIRC\ (or c:\program files (x86)\mIRC\ on a 64 bit computer). You access it like any other program. Open on the start menu and click on Computer and browse to the folder.

If you have mIRC running, you can find where it's installed by typing in mIRC: //echo -a $mircexe

If you want to know where mIRC's settings are stored, you can type in mIRC: //echo -a $mircdir

You can access it by using the command "/run ." inside mIRC