You can collaborate on a broadcast in a number of ways. The easiest is just to add a text or mobile box, choose a unique email address for the box, and provide it to your collaborator. Any time he or she emails something to that address, it will be added to your broadcast. You can title the column with either a graphic or another text box, such as "Aunt Sara's Recipes."
You're just going to practice this now, then we'll show you how to delete any item box.
Remember, if this were a real collaboration, you would make note of the email address and give it to your collaborator.
If your collaborators want to send in photos via email, just have them send them as attachments to the special email address.