To only include certain decks, you need to modify the Search filter.
E.g.
-
introduced:1 deck:"Deck 1"
will only include cards that were introduced today that belong to Deck 1. -
introduced:1 (deck:"Deck 1" or deck:"Deck 2" or deck:"Deck 3")
will include cards that were introduced today that belong either to Deck 1, Deck 2 or Deck 3.
(replace Deck 1, Deck 2 etc. with the names of the decks you want to study)
See this for more info about how Search filters work: Searching - Anki Manual