Equally though, when you think you've finished it; have a read / watch about all the fantastic things that you missed.
The entire project, and including the journal on the Google drive, is just incredible.
I very much enjoyed this video that goes through all the content:
https://www.youtube.com/watch?v=5wAo54DHDY0
Also, this one to learn about the methods used to create "myhouse" in the doom2 engine.