Requirement of Auto CAD installation. 

• A laptop with Windows/Mac/iOS and Android operating system with at least one GB RAM.

Graphics Card, and Auto CAD software which version you want. You can install latest or previous version of Auto CAD. You Can Download trial version of software from Autodesk official website from this link. http://www.autodesk.com/products/autodesk-autocad/overview 

What is the differences among Auto CAD, Auto CAD LT and Auto CAD 360.

Auto cad and Auto cad LT are prefer with Computer while Auto cad 360 is prefer with Mobile Phone. But on Auto cad we can create 2d and 3d while on Auto cad LT we can only create 2d object.