Do not know what is wrong by the shortcut keys, can not switch the layer sound and display button. Ask the old driver to tell.
Move the current time point to * seconds (any number of seconds you need to keep), adjust the value to 100 (or whatever you want the size), it will automatically record the key frame.
Drag the current timeline to preview.
Click on the keyboard S key, will pop up a parameter layer;
Click the stopwatch shape button in front of the parameter layer to set the key frame at 0 seconds with a value of 0;
Strongly recommended in English.
In the timeline panel, select that layer (pictures, videos, text can be);
