I want to down load app to my ad card so I can download mode apps but it won't let me download apps to it and still play them
You can install Link2SD. Its an app in the Playstore. But you need a rooted device.
Also if you want to move
.obb files to your SDcard, you need to pay for it.
There is also a "How to" in the description of the app in the Playstore.