Now the time is for using your own skills for adding stair etc. to the model. You can add the stair to the Left side of the model by just adding/clonning some boxes.
Add some walls also to the model again by just adding some boxes and adjusting their scale/parameters.
Continue to adjust all the things as your wish until you get the desired result. Also you may like to apply color/materials as your preference. That is up to you. Bye for now.
We have just opened our tutorial directory! Feel free to submit tutorials hosted on your website or other online tutorials that you think are worth mentioning.