Hunting Party Challenges are automatically completed as soon as you have completed a weeks worth of challenges. Once completing a weeks worth of challenges, you will unlock a loading screen. These loading screens have clues to either a hidden Battle Star or a Banner that can be found in the Fortnite map. When you have completed five weeks challenges, you will unlock the following loading screen:The loading screen for the Hunting Party Week #5, there is a hidden Battle Star. We have highlighted the Battle Star in the image below:
The location of the Battle Star is of course in the Castle shown in the loading screen and can be found on the mountain east of Haunted Hills. We have marked this location on the map below.
The Battle Star will be in the window, so you could either land at the top and break down or you could build up to it. The Battle Star will only appear when this loading screen has been unlocked.