How can you add an individual contact to a smart list?
Go to the individual contact record and add the contact to the desired smart list.
You shouldn’t do this because this would change the logic of the smart list and would remove other contacts from the list.
You won’t need to add an individual contact to a smart list because they will already be on the list.
Import the desired contact into the smart list.
https://www.youtube.com/watch?v=G6Efvvtz-qY