So, the main mod has been released - to install, (I've seen some people have issues with this) you need to simply download, then place the Eternium1 folder into your main Amnesia: The Dark Descent folder, (redist for non-steam users) also, If it asks for a serial code you can find one here:
It can be accessed and copied directly from the file \Documents\Amnesia\Main\installkey.
Make sure that you install correctly otherwise it will effectively ruin Amnesia: The Dark Descent.
If you have technical issues, do not hesitate to post them! I'll do my best to solve any and all issues that arise from the release of my mod.