When you are in edit mode for your hub, there is a section to the right that lets you reorder your capsules like your text, photos, etc. You simpy click them and drag them up or down. Well in the same area that are different tabs to go over to something different. One of those taps is Summary. You then simply type a short summary into the box and click done editing or publish when your'e ready. In that same area some of the tabs are Reorder, Tags, Summary, and Groups.