There's actually a really easy way of doing this.
Right click and 'insert empty event'

Stretch out the empty even to the full length of your song or however long you want the bars to be there for (I already put the bars in that pic)

Put the cookie cutter effect into the empty event and set it to square with a black border (for black lines)
(put up the Repeat Y to make it just lines) and use the size and position to set it just how you want it.

Use keyframes to change the position to where ever you want it to be throughout your video. Because it's one single media even you can make it flow as smoothly or sharply as you want. You can also set it to nothing when you don't want it ....ect. using the keyframes.

I think this is what you are trying to do. Pretty simple right
