Creating the best navigation for an app showing Youtube videos

I am creating an app that shows educational videos that are classified according to Grade and Subject, How do I create the navigation such that on one screen, students select a subject, in the next screen, students select the Grade and in the third screen, all the videos for that subject and grade are shown.

I have a sheet that contains all the videos with Grade and subject names.

Thanks in advance.

Have a “Selection” sheet with 2 user-specific columns to store those Grade and Subject selections (I suppose you can do this in one screen instead of two, if you need to do so).

Then have a template column joining those 2 columns. In the videos sheet, have a similar template column joining the Grade & Subject as well (make sure the format is similar).

Then back to the “Selection” sheet, make a multiple matching relation column that pulls back all matching rows for the template column you have created. Show that relation to the user.