Boost is a feature that makes your profile visible to more users for a limited period of time. Once you complete your Boost purchase, your first Boost will be activated immediately. The navigation bar at the bottom of your screen will turn purple to indicate that your profile is being Boosted.
At the end of your Boost period, you will see a pop-up from the bottom of the app telling you that your Boost is complete.
Other users will not see that you have purchased Boost or that your profile is being Boosted.
To purchase a Boost, go to your Likes You screen and tap the Boost button:
You'll know that your Boost is active when the Boost button changes to say "Boosting" instead of "Boost." You'll also see the navigation bar turn from black to purple:
When you receive a like that was a direct result of your Boost, you'll see a small lightning bolt next to the name of the person who liked you.
When one of those Likes becomes a Match, you'll see another small lighting bolt next to the user's name: