Yesterday was the LEGO Stranger Things event at the Flatiron and Leicester LEGO Brand Stores and if you attended, there was also a building event for a make and take for the Castle Byers build. A user on Reddit has provided the building instructions for Castle Byers but the stickers are exclusive to that set. The parts needed for the build are as follows:
The LEGO Stranger Things The Upside Down (75810) is now available for purchase for VIP members for $199.99. It will be available to the general public on June 1.