I can't figure out a way to do this. on a certain number of frames I want "hi" and on another number I want "bye" But the first text is on all the other frames.
Movie, Video or animated gif?? adding clipping mask to a series of frames may be what you want to do.
when working with frames, you need to think layers, Make sure the correct text is on the correct layers and not any of others. If you want anything in between the two text layers, you need to add them when creating the frames. If you add layers later on it is quicker to clear the frames and regenerate from layers.