Freud se stal z malého doktůrka velký psychoanalytik.

The main verb is "stal se" 3sg. past tense form of stát se 'to become' and takes the instrumental case

The subject is the nominative form Freud.

z malého doktůrka is a prepositional phrase with the prepsotion "z" taking the genitive cas

What is missing is the X in the instrumental case in "Freud became X"