Question

How does the kinetic molecular theory help explain the difference between solids, liquids, and gases?

Would the answer be basically stating how the theory states the difference of their atom structure?
Or is it something else?

Answer 1

I think you want to focus on the attractive forces between molecules, the space between molecules, and things like that. Here is a good link that talks about the KMT and you should get a lot of ideas from that.
http://chemwiki.ucdavis.edu/?title=Textbook_Maps/General_Chemistry_Textbook_Maps/Map:_Brown,_LeMay,_%26_Bursten_%22Chemistry:_The_Central_Science%22/11._Liquids_and_Intermolecular_Forces/11.1:_A_Molecular_Comparison_of_Gases,_Liquids,_and_Solids