lol you need to add more edges to create flat surfaces and hold geometry if you're using the smooth modifier...  seems like you jumped into using TSplines without going through the manual.. might want to do that first

man its one of those times when you just have to jump into modelling, i couldn't figure it out in other programs. I tried Setpt, and flatten points through Tsplines.. they show it in TSpline tutorial but that didn't work out. My school is no help, prof who know how is apparently too busy. I appreciate all the help. This literally is the last forum now, i tried everywhere :/ 

while i figured out somethings, I am still struggling with the stairs part and i looked into the manual too. I am at a point where I am willing to pay someone to help me do the rest lol 

loll tip: Do not try and learn a new software when you have a deadline.. Use whatever software/method that will get the job done on time, whether its some complex coding or having to use mouse clicks a thousand times xD

back to your question..  model your stairs separately from your building model.. Do not apply the 'sub-d  or smooth modifier or whatever you call it in t-splines.  leave it hard edge

I didn't know how else to do the model with limited software skills lol, i modeled it separately now I am trying to merge them

hmmm it seems like you still need to learn the basics of sub-d modeling... here is a good tutorial on hard edge modeling using 3DS Max but the techniques can be applied to tsplines or any other polygon modeling software.  take a look in the first 6 mins and you should get an idea of how to create edges to hold hard edge geometry

https://vimeo.com/10941211

there is also a way to add weights to points in t-splines, that plus actually getting more edges/points into the model should work...

in all sincerity though, you're using t-splines the wrong way if you need a truly flat surface out of your t-splines solid... i'd model the flat surface with rhino solids/surfaces and actually figure out how it comes together with the other parts of the model.

i fixed everything except the stairs, i have modelled stairs in rhino but i cant figure out how to merge those stairs with the model