When you swipe left on a profile, that means you are not interested in them. When you swipe right on a profile (or tap on the ❤️ if you are viewing their profile from the community) then that means you are interested in them. A notification will then be sent to the person and if they like you back you will be sent a notification that you received a match and a chat box will become available for you to begin talking.

Profiles that you've swiped left on previously could appear again in your Meet section after you've swiped through all the profiles.