Documentation wise, there is not much to it beyond "load the extension" but it can still be well documented.
- Detail every step
- Detail every detail
- Make no assumptions at all (e.g, "just start it with --require option, is bad and not explicit enough)
- Pictures is okay, thingamajig is basically an extension, even when running as a site script.
Documentation wise, there is not much to it beyond "load the extension" but it can still be well documented.