How to Insert Silence?

I want to insert 5 seconds of silence under an image at the beginning of a project, before the audio (music) starts.

I tried pinning the first music track to the spot I wanted it to begin -- however, the #2 music track automatically moves up into the blank 5 sec space at the beginning.

If I pin all the tracks to each other, I can't edit or move images without things getting screwed up.

So: how do I insert silence at the beginning of a project or between tracks?

Thanks.