First you have to duplicate the scenes in the project panel. Click on scenes 3 and 4 and go to edit>duplicate or cmd+d. Then, double click on the the comp named “Color Control” right from the layer panel from within the “final comp”
I can’t say for sure, as I don’t know how that template is set up. But I’d bet you’ll see the scene comps laid out within the Color Control Comp.
If that’s the case you can drag your new scene 3 and 4 comps into there and move them into the correct position on the timeline. You’ll most likely have to make that comp longer, along with the “final comp” to fit these two new scenes. go to composition> Comp settings or cmd+K and you can change the duration in there.
if the scene comps aren’t in the color control comp, just click on one of the scene comps in the project window and click on the arrow next to the name at the top by the thumbnail. That’ll tell you where the comp is being used in the project.