How to attach Floaty orange foam to back door of GoPro

Two things confused me when I opened the package.

1) Why are there two different plastic doors provided? I found the answer on the GoPro.com website, after finding no instructions on the package. One is for the dive housing, and one is for the standard housing that comes with the camera.

2) How to you peel off the backing so you can stick the foam on? I tried tugging at the orange tape, but it looked several times like I'd ruin the dense grey foam underneath. I didn't want to tear the grey foam. However, that whole orange backing has to be parted from the slim grey foam, so that the orange foam block can then be firmly pressed on (centre first so you don't get air bubbles) with some give provided by the grey stick foam which is very sticky when that orange peeling is removed. I got the sticky grey foam exposed, hovered the orange block over the standard housing (I don't have a dive housing) and pressed down evenly and hard. I should've pressed in the centre first to squeeze out air, but still it seems very firmly affixed now.

Then, I needed to learn how to switch doors from the standard see-through to my new Floaty orange back door. It turns out it's very easy. The manual (downloadable from GoPro.com) shows exactly how to do it, and basically you open the housing all the way, and pull straight down so the door unseats itself from the bottom of the plastic hinge. I wonder how the plastic will hold up to frequent use, changing between the standard, open-back, and Floaty back doors. Let's hope it's really sturdy plastic, as it seems to be.