Hi.Where i can find information about unity engine architecture, how it work…
Unity has their own site containing alot of tutorials, also if you are starting out i recomend the TornadoTwins tutorial series on youtube: How To Make A Video Game [Unity3D Basics] Part 1 - YouTube
In there they explain alot about how the diferent assets come together.
I hope this was helpfull at all, cheers 