This is a The Big Lebowski puzzle. The quotes under "Word Bank" are each missing a word, and those are the inputs for the three minipuzzles.
The inputs for the first puzzle (which you kind of just have to figure out by process of elimination) are BRAIN, FIXES, LIKE, OWES, ROUNDLY, and THOUSAND. Rearrange the indicated letters as instructed, and you get the quote "Seek and you shall find." The source of this quote is JESUS.
The inputs for the second puzzle are the shortest words in the word bank, the five three-letter words EAT, ACT, ITS, TOE, and CRY. Read down the middle letters to get the answer, ACTOR.
The clues in the third puzzle are for words that each represent one of the input words with a single extra letter inserted. The clued words are DESSERT, CAUSE, CROCK, SNAPS, COAST, MORMONS, and CARED, and the extra letters spell SURNAME.
The actor who played Jesus Quintana in The Big Lebowski is John Turturro, so the answer is TURTURRO.