How to enable sub decks

Hello how I get the little drop-down menu that shows all the subjects in the Anking deck. It used to show for me until i played with a setting called sub decks and it disappeared. I have been unable to get it back even after redownloading the deck.

This was only present in V11, not with V12 on AnkiHub. You can enable subdecks like this below but it will not show any subjects. The reason for this can be found in the wiki.

Please refer to the AnKing deck Wiki for further info: Notion – The all-in-one workspace for your notes, tasks, wikis, and databases.

See the bottom right of the image