Hasta La Motion!

I am attempting to track the ground of this shot so i can place text onto it. I’m using a single camera with free motion and my focal length is constant but unknown. i am tracking a few points with user features only. (all seems to work fine since my earlier beginner post).

Now what i cant seem to wrap my head around is in the perspective view when i am attempting to orient my scene my features are all over in 3d space. how is it that i can get all the features to be on the same plane?

i attached a screen grab for a visual. if i am missing any information you might need to help please let me know.

thanks much.
alex