After the pack has been downloaded, click on the bubble under your game menu (just like you would install any other downloaded item).At this point, it will prompt you to hook up your Play Station Vita and run the content manager.
If it’s already there, you should see a “remote play” screen.
Now, go back to your Play Station Vita and launch the LBP 2 cross-controller app from the Live Area.
From there, follow the steps to connect your PS3 to your Vita and install the LBP 2 Cross-Controller content on your Vita.
Once this is completed, you can disconnect your Vita from your PS3 and close the Content Manager.
On the “Remote Play” app, you will see “cross-controller.” Click “Cross Controller.” Follow the on-screen instructions and click “next”.