Opt in to Arcade Challenges on the Ubisoft Club website or with the Ubisoft Club app. More information on how to do that in this article.
To complete an Arcade Challenge, play on maps on the Far Cry 5 Arcade mode and achieve the defined goal. To find out what Arcade Challenges are happening, which ones are coming up next and how far you have progressed towards the goal, please visit the Ubisoft Club.
For each Arcade Challenge you complete, you'll receive a reward on the Ubisoft Club that you will be able to claim. The reward will then become available to you in-game.
Any questions, feel free to get in touch!