If you’re using one of the builtin themes then. .content is probably what you want. It’s any dom selector nested within your html form that you’re trying to access.
If you look inside standard-page.html you’ll find a div with that class.
“world” is just an argument being passed to the function. You can pass arbitrarily many arguments. If you don’t need to pass any arguments then leave this blank. But it looks like you need to pass either 1 or 0.
You may want to re-read the docs and which covers this