Open the PBS app and navigate to a video you want to watch. Begin playing the video.
Using the directional pad on your Fire TV remote, press the down button. The video progress bar will appear, along with CC and settings options at the bottom left. Select the CC option.
A menu of CC options will appear in the bottom right corner. Select English, CC. Select the Off option if you wish to turn CC off.
Press the menu button on your remote to return to the video.