To start using DesignStudio or CineStudio, download and install mExtension, the new app that enables you to browse, download, and apply elements directly to your timeline without leaving FCP. In the installation process, you will be asked if you want to install the mCaptions plugin (we highly recommend it!) and to activate the device you are currently working on. Voilà!
Now, you can easily download and drag-and-drop elements to your timeline.
Here's a quick and easy tutorial: