Synching Sales/Promotions to Countdown Timer

Hi,
I want to set my timer to recurring constant countdowns.

I want to set it to countdown 4 days, wait 1 day (or 7 hours) and then start again.

I believe I set that up using evergreen and the “wait” function. That’s great and I am happy!

BUT – how do I sync my actual promotions with the countdown?
For example, Can I set a 25% off the whole shop when the countdown is running?

Thanks!