How to Filter and Send the First 20 Rows Daily in Your Sheet

Hi Everyone, I am trying to create a column that lists each row as a number for filtering based on a Date Added column. Basically I want to send the first 20 rows each day to Lemlist and any further rows for the day to instantly. If someone has built something similar or has a way of defining the first 20 rows per day I'd appreciate some help / insight to how it can be achieved. Thanks everyone!