It’s always best to search the forum for similar topics before posting. There should be a few that already discuss this workflow and can get you started.
Keep in mind a Revit schedule is just a view of project elements and their properties. You typically don’t add data directly to a Revit schedule, you add data to an element that is visible in a Revit schedule. It seems you’re dealing with Areas which happen to be one of the few schedule types where you can add some data directly, but you’ll still have to create the elements to get the data you’re looking for.