Read your original paper closely and carefully.
Print the document out and use old-fashioned writing technologies like pens and highlighters to outline and analyze your original content. What are the major parts of the original argument? What smaller parts are large sections made up of?
You could even get out scissors and literally cut it up into different sections.
The “required elements” section provides some minimal requirements for parts you’ll include, but your webtext will need to be broken down beyond what that list suggests.