In the lesson below, it is stated that "se coucher" means "to go to bed"
Conjugate reflexive verb se coucher in the present tense in French (Le Présent)
However, when I wrote "puis il se couche" as corresponding sentence for "then he goes to bed" in the last part of the exercise, it was marked as a mistake and the correct one shown as "puis il va se coucher"
Could you please advise which one is correct ? or have I misunderstood something ?