I built a house which only took me an hour, however, that's actually alot of time in my perspective, and while mesmerized with the building, I forgot to plan (I never plan stuff out, it sorta just comes as I go) and add the most basic part, the foundation. Which leads me to my question, can I add a foundation to an existing house? I am willing to use any means necessary, besides rebuilding the house from scratch all over again.

Unfortunately, there's no other way than rebuilding, as the foundation is recognized as the "first floor" of your home. I would just leave it the way it is. Not every home needs a foundation!

Eh, there goes the porch stairs, well thanks for the help. I'll think of something else to make the porch better.