In step 4, one can indicate what a guest's history must satisfy to qualify for an Email selection. (Step 4 only affects the reservations that meet the criteria of step 3). For example, that X amount of sales has been generated by the guest's stay in the hotel, or that the total number of nights that the guest has spent in the hotel is more or less than X.
This step can greatly reduce the number of people you get on your mailing list and is not recommended for new users
One can proceed to step 5 after these criteria have also been entered according to one's wishes.