Thanks, Cathal! I guess it was the "Forms 1.0" that threw me. Makes it sound like an obsolete solution.
In any event, shouldn't the article with the broken link be updated? I was initially looking for a way to report that, but it doesn't appear to be an option in submitting a support ticket; and there is no way to comment on that particular article:
https://community.marketo.com/MarketoResource?id=kA650000000GsXXCA0