I´ve done some research and I think this will help you:
1 - Copy the folder address where the downloaded content is.
2 - In CA5, go to the Content Manager window, select Custom and on the left side choose Scene.
3 - On the right side there is a down arrow. Click on it and select Smart Import Custom Content.
4 - On the address field, paste the folder address you copied in the first step.
5 - Click Select Folder, and all the content there is inside the folder will be imported to your Content Manager.
Let me know if that helped.