How to play custom PWADS on doom 64EX?

I know it involves putting some text into the bottom bar of the launcher, but aren't sure of what I need to type. I've seen the format as something like "-file****", but am not sure what that means. The wad I want to play is EARTH FINAL_8. Can someone type exactly how I'm supposed to input that? It's probably super simple, but I am super lost.

-file EARTH FINAL_8.wad

That is if you put the wad alongside the EXE.

Or you could just drag and drop.

This should work as a batch file or shortcut:

doom64.exe -file "EARTH FINAL_8.wad"