How do the batteries fit in a 2 button mondeo remote key?

Hi, bought a secondhand mondeo for my sister, remote 2 button key didn't work, seller said the batteries were flat. No problem, asked my nephew to see what batteries were in it, so as I could get some new ones. He popped the key apart and said there were 2 CR2016 batteries in there and a flat metal separating disc, what the prat didn't take any notice of was, how they all fitted in there. Obviously I need to get the 2 batteries and the disc back in the correct order before I reprogram the key. Anybody out there help me?

Bill