RUSH rewards are gifted to users who have connected certain game accounts to the Player Rush site. These rewards are given for a few different actions those players perform in those games.
To gain RUSH Rewards by playing Fortnite you must first connect your account to the Player Rush site. To see how to do that please check out our article on Connecting Fortnite to Player Rush.
Once you have connected your account you can visit your Player Rush Fortnite Dashboard.
There you will See your stats and rewards for Fortnite, as well as the Player Rush Fortnite Leaderboard. Player Rush members are rewarded with RUSH rewards for killing opponents inside of Fornite Battle Royale games. The amounts vary depending on the type of Battle Royale you play, but you gain RUSH Rewards for every kill you make playing Fortnite.