Answer
Create the custom entity with its attributes and publish it; create a new Projection Configuration and add that entity to it; go to Page Configurations and create a new page based on that projection; open the page in Page Designer, switch to the appropriate configuration context, and set the page's Entity and Data Source Entity Set; under All Elements, create a new List bound to your entity with the attributes you want shown, then add that list under the Active Page's Contents; finally, go to Navigator Configurations and add the new page under whichever node makes sense (the exact client/page name needed for this can be read directly out of the page's own URL once it's built).