CP2019 I have a project that I want the student to view the whole slide before advancing

You need to get rid of the default playbar, sorry.  At least the scrubbing bar and the Next button needs to be taken out. Do you also want to have the same situation when the learner comes back to the slide? If not, have a look at:

http://blog.lilybiri.com/play-audio-once-on-first-visit

I also have a follow up blog, where a shared action is used.

If you don't want this scenario, you could use the Delay action On Enter for the slides, but anyway you would need a custom Next button. It could be the same button on the first slide, timed for the rest of the project. For the On Enter action use this:

Hide Bt_Next

Delay Next actions by x secs                         where x is the duration of the audio clip

Show Bt_Next

This advanced action could also be converted to a shared action, for more flexibility. Two parameters needed: the x (duration of clip) and the button Bt_Next. Since it has been timed for the rest of the project, same button ID can be used.

Have to warn however: the Delay time will not take into account a possible pause in the slide.