Installing Monterey on MBP Late 2013

Hello, I’m trying to install Mac OS Monterey, on my late 2013 MacBook Pro, using the OpenCore Legacy Patcher. I have downloaded the .dmg file, as instructed, moved the files to the /applications folder, as listed. Now, trying to do the next step, createinstallmedia. But am getting the following error: “command not found”

Can someone please tell me what I’m doing wrong? I can’t get past this step. Thanks! Dave Salsbury