I’m new to both programs, i tried very hard to construct a basic house in blender but once it was exported to unity not only could i walk through walls but i was falling right through the plane everytime. I must be missing something, is there an option or certain way to build in blender to not have a plane and cube completely just let me go through them? or am i doing something wrong in unity? if anyone has any link to tutorial to fix i would appreciate it, also like i said im very new to both so explain in detail if you respond please 
thanks
You need to have a collider on your house. The easiest way to do this to check “generate mesh collider” on the import settings. However, if you want more control, you’ll have to use box colliders and cylinder colliders. When using those, the green box represents the “hit box”. They are found under
Components->Physics->Box Collider/Mesh Collider/etc