Glad that helped!
For pages designed to look at a single record at a time, the Page Designer app is fairly straight-forward. It gets a bit more tricky (trial and error) when attempting to create a page design that employs information from multiple records onto one “page.” This is discussed to some extent in that other community post I linked to in my last message.
The grouping and filtering capability occurs within the parameters that you set up within the view that the page designer app is looking at. It’s good to think of Apps, in general, as a way to organize or view information coming from the Airtable base/table/view/record. Some customization options exist within Apps, but much of the customization occurs in the tables and views you’ve set up. More on the general overview of Apps here.