How to turn on closed captioning for all slides at once in Storyline 360.

I have about 35 slides. I added the CC option to the player thinking this would allow cc to be turned on from the player for each slide. However is seems you must go to each slide and check the box to generate captions per slide, then the player cc button is visible. How do I turn on closed captioning for all slides in the project without having to go to each individual slide and check the cc box is this possible?

Thanks