Thanks Taffer. Mickhah, follow the link Taffer gave. For standalone installations, download the
patch instead.
To install simply unzip the pack, copy and paste the contents into the DF directory. Overwrite files when it prompts and play. If you have preexisting saves where you would like to use Obsidian on, copy the
raw folder of the Obsidian pack and paste it into the specific save folder you want to use. Overwrite when prompted. (I've added this to the instructions in the main thread now)
I highly recommend you backup your entire Dwarf Fortress folder first, in case something goes wrong.
(This thread should also be moved to DF Modding rather than here, this sub-board is for releases only)