Scenery download is here: 88NV Black Rock City Airport - Scenery Packages (v11,v 10, v9) - X-Plane.Org Forum
You’ll need to make sure you’ve updated The Handy Objects library and Opensceneryx recently-ish. The other library hasn’t been updated in a couple years so as long as you have it you’re good. Requirements listed on the download page.
If you want to follow this with the EPOCH pilots themselves, then you can go to www.unex-planedapps.com and create an account. Most will be posting there instead of the org site.
I’ve already landed at Burning Man as part of the fly-in experience over the past few weeks (though I missed the majority of the actual fly-ins). Make sure you read the documentation, it’s extremely helpful, and will be necessary to properly complete the ‘daily’ activities.