You can draw it in x,y,z and use reshape and divide area commands may help you to edit it to the way you want it to model.
The SAP2000 manual and Analysis Reference guide under the help menu may have additional information. I am somewhat new to SAP2000 as well.
Their youtube tutorials on their website are pretty good. There is a drawing tutorial. They are not in-depth but do try to cover how to draw various objects including shells without getting into the modeling aspects in that tutorial. Computer & Structures (CSI) website or google search should bring them up.