It may seem daunting but you can use Node view, or as Opentoonz calls it, Scene schematics. This is where you tell the different drawing layers what to do and add effects.
This guy explains how to use a matte. But essentially you want to draw a big red square on its own layer where you DON'T want scene 1 to be seen.
You'll use FX schematics (button in lower bottom in scene schematics.) and the FX "Matte out". Plug in your big red square into the matte red triangle "Matte". and Scene 1 into "Source" (or everything in Scene 1. Group everything in Scene 1 together!)
Group everything in Scene 2 together once you animate it all and give it a peg (it will make everything easier down the line.) I used a peg here for my Matte and Lamp so that they move together when I animate the peg. You can animate pegs just like layers they just move everything they're connected to.
So what happens is that the matte covers up Scene 1 like an invisiblity cloak and shows you scene 2 underneath scene 1. Use that eye in the top right corner that turns green for render view or how it will look when exported.
It took me a second to figure this out! Opentoonz is quite tricky! It's really impressive seeing your animation come together in it!
There's also a way to use Z-depth to make all the layers move without having to animate them all. Like multiplaning, but. . . That's a whole other thing.