Creating enterable buildings Im new to blender itself so I was wondering if anyone knew anywhere good to learn how to use it, Im fairly quick on the pickup with a good guide on hand.
Anyway Ive been looking all over the internet and can't find anything to help in regards with this.

Im looking for a good way to create from scratch multiple different building structures that can be exported for later use into my gaming enviroment in Unity.
I have no issue building them one by one over time. So if there's something that'll help me render them before moving onto intricate inside details, awesome! (I came to Blender because it seems to be the most commonly noted one for this task, but can't find any guides to do this) 
Anyway any help on getting started and working through all this would be massively appreciated.

Thank you in advance.
Best begginers tutorials i know are at gryllus.net after finishing all tutorials in there you can just pick some from blender tutorials. As for enter-able buildings: just move pivot point to the edge of door so you can rotate around it, and animate it so it will look like door opening.
Example: