I am doing a tutorial in that duration in composition panel was set to 20 sec. But layer duration is 5 sec. Is there any issue in draging the layers and making it 20 sec?
If your media is 20 seconds long, you can stretch it till you hit the 20 seconds. It won't let us stretch beyond that.
Hope it helps.
Why does it show 5 sec?
The traffic cone icon may indicate that the layers are from a PSD file if you have the VLC player installed. If that is the case, you can make a PSD layer, an Illustrator layer, a solid, a shape layer, or a text layer, any length you like.