Thanks so much for your help here, Josh. Unfortunately I'm still stuck.
What I want to do is send an email to users on the anniversary of the date they registered for our website.
Our RegistrationDate field is definitely a date field.
I've included a screen shot of the Flow tab below.
What should I put for the trigger (or just generally what should I put in the Smart List area)? I tried RegistrationDate "in past 1 day", but that's only people that registered yesterday, not people who have yesterday as their annivesary.
Thanks in advance for any additional guidance you can offer.