Hiding and showing Next Button in slide

Hi,

I am relatively new to Storyline 360.

I am feeling challenged attempting something I thought/hoped might be easy and would appreciate any guidance.

I have an audio file, with linked images playing in a slide.
Initially I do not want users to be able to progress to the next slide till they have listened and viewed the whole timeline.

Hence I have hidden the next button.

After viewing the slide once, I want viewers, if they return to it to the slide,  to be able to fast forward through this slide or select it mid way through the slide.

How can I hide the next button for the first viewing, and make it visible for future viewings?

Kind regards

Andrew