When you are on the way back, this is where you can connect the keyboard lighting. You put the flat cable from the new keyboard into the connector directly to the right of the one for the keyboard ribbon cable. It shows itself!

My subwoofer has two screws

I left it in place. It was not necessary to remove it for replacement of the keyboard.

It was not necessary to remove this item for me. I could remove the keyboard with it in place

I had only 59 screws, still it seems OK..