Sorry, I'm very inexperienced with this kind of bookings (free stopovers). What exactly do I enter into the multi-city search? Should I enter every flight separately? And how do I see which dates are available at the good price?
Example: I want to add two days in NYC (EWR) on the outbound leg. I enter all the flights separately LIS-EWR, EWR-IAH, IAH-GIG (the last two being on the same day). I get a much higher price. Is there a fast way to check on which day the price would remain the same?