Solution to Back School To

The title is an alphabetization of the phrase "back to school". Following the theme, each list is a list of book titles from a children's book series, but alphabetized. In turn, the lists are themselves sorted alphabetically by the first title.

All occurrences of the letter "A" in the first list, the letter "B" in the second list etc. are replaced with an emoji that clues which book series it represents. On top of this, one additional letter from each list is emojified, serving as extraction letters.

Finally, as clued by the arrow going to a new list below, the book titles carrying extraction letters must be sorted alphabetically. Reading off the extraction letters in this new order gives the thematic final answer PLAYSETS (though solvers may also arrive at this earlier by anagramming).