Is this in Premiere Pro CC?
Nope, Photoshop CC.
My process is Create a Film and Video Document, Add a new blank video layer, start animating.
But the default layer only has 120 frames (5 secs). I need a way to add more frames to the existing layer.
There is one work around I just found, when I reach the end of the 120 frames and insert a frame, the layer does in fact increase in length. But it involved drawing a frame, hotkey to insert a new blank frame, going to the timeline to extend the video bar because it doesn't automatically extend, then going to draw again, and repeat.
There must be a setting somewhere to change the overall duration to be more than the default 5 seconds.
In previous versions of photoshop it was under the Animation Panel Settings --> Document Settings. Which no longer exists.
Moved from Cloud forum to Photoshop forum