As you click this link, you are transferred to the "edit" feature of the new page to be created. You just type into that window whatever you want to see on your new page and then save it.
Note: each time you click "save", this is recorded in the statistics of the Rhea. As you are experimenting with the look and feel of the page you design, it is better to click "show preview". To see why, suppose you did 15 iterations until you were happy with the page. If you saved each time, you will then be shown to have made 15 changes to the Rhea. Of course, that's misleading. Once there is a reasonable amount of material on this Rhea, people will start looking for "recent changes" by clicking on the appropriate button on the main page and in a perfect world only actual changes should be registered there, not iterations towards a final goal.
Of course, once the page looks like you want, you _must_ click "save".