Moving a block of the same-named Layer around in a file

I know there is a solution for this, but I lost my notes!

I work in another program for art. I create filled-in characters on a clear background, with a background underneath–two layers. Often, 800+ panels.

Then, I export 800 panels of character action, and 800 panels of backgrounds from that other program. Then, I ‘Import > Images as Scenes’ twice into Storyboard Pro.

That gives me 800 panels of character action in my Timeline, followed by 800 panels of backgrounds.

I need to move the 800 panels of character action on top of the 800 panels of backgrounds, and I’ve lost my notes about how to do this.

I believe? that first I have to Rename my panels, so that the 800 layers I’m moving all had the same name ‘Characters’, instead of ‘Characters0001, 0002, etc’.

Then, I’ve forgotten how to select the same layer across a series of panels,…that’s key…and then move them onto another series of panels…to take my 1600 panels (800 or characters, 800 of backgrounds), and make them 800 panels.

Can you help?