First of all go to this link to download the software
http://usa.autodesk.com/autocad/trial/
Then after downloading the software ,open the setup and wait a few minutes, Just as picture show
Then press INSTALL button after Choose your location to install, as picture shown
After that click the ACCEPT button ,Then click next , like the picture shown
If you have the serial key ,enter it and click next to processing
Last but not least ,Click INSTALL button to began installing
Now wait a few minutes to complete installing
Finally click FINISH button and enjoy !!
http://usa.autodesk.com/autocad/trial/
Then after downloading the software ,open the setup and wait a few minutes, Just as picture show
Then press INSTALL button after Choose your location to install, as picture shown
After that click the ACCEPT button ,Then click next , like the picture shown
If you have the serial key ,enter it and click next to processing
Last but not least ,Click INSTALL button to began installing
Now wait a few minutes to complete installing
Finally click FINISH button and enjoy !!