Command tutorial?

Throughout the Opus videos and help files, I see reference to "entering a command" on the command bar. I've had Opus for a few years now but I have not ventured into using commands. Plus I can't find out where to even enter them! Is there a tutorial anywhere on this (including scripts too)? I've searched the forums, help file, youtube, and can't find how to get started.

The commands are the same ones that run in all toolbar buttons and most hotkeys. If you click the small Commands link at the top right here, they're all described there.

F1 in the button/hotkey editors will also take you to the same section of the manual, jumping to the docs for the command on the same line you were on, if there is one.

You can type > into the file display to open a command field where you can type one-off commands to test them or do things that you don't want to create a temporary button for.