Skyrim: Apochryphal Hearthfires
The Hearthfires DLC for Skyrim adds the ability to build your own home in three different locations around the province, providing player homes in holds that didn't have one in the city. Unfortunately, all the houses are essentially the same, with no variation in architectural style, and the choices are limited to three wing layouts for each of the three available sides of the main hall. There was some indication that texture sets were intended to be used to make the homes distinct, but that didn't happen.
So I created a series of BYO homes for various races, and now we move on to the realm of Hermaeus Mora with library home.
The quest
Before you can start the quest for building the home, you need to find the Black Book that transports you there. You will find a library already in place, with a resident Librarian named Bibliophilia, who is curating Mora's collection of pornography.
Existing rooms
There is an area where she sorts the books, shelving the good ones, and discarding the damaged and duplicate ones. These latter become part of your building materials, but you'll need to fetch other materials from Tamriel. There are bookshelves for the books that are being kept, and several piles of unsorted tomes in the room. On the table is a ledger where she reocords her findings.
The librarian already has her own room, off the sorting area. She has a single bed, table and chairs, shelves and a cookpot, so she's quite comfortable before you arrive and start the expansion. You'll notice that she sometimes takes her work with her, as there's at least one pile of unsorted books, and a few select volumes in her private space.
On the opposite side is a forge, with associated benches, that you don't need to construct.
The back of the sorting area will lead to the central hall, once you start construction.
Construction
You have the choice of several rooms that can be added, but the central hall must be created first. This will have the book portals that lead to all the other rooms. The exception is the Garden, where the space already exists, and you just need to add benches, planters etc.