Hey @sarah.g,
Welcome back to the Community!
Since Black Friday/Cyber Monday are such specific dates, using a date filter to target users who have purchased during Friday is usually the easiest method. Another alternative strategy you can use would be if you grouped all your Black Friday specific promotional products in their own category. This way you can segment and identify users who have purchased products from this specific promotional category.
You could even combine both of these strategies to get more specific grouping of individuals who purchased or not purchased during this time frame. For example, if someone bought a shirt on Black Friday that was in the Black Friday promotional category, you could then cross sell pants that are in the Cyber Monday promotional category on Monday.
This is just an example, but you could certainly do a lot more! It all depends on how you want to segment and target your own customers.
I hope this helps!
David