Grab the frontplate like shown

Lift the frontplate up and away

Start to lift the top part upwards

While lifting, try to unhook the bottom catches to let you lift the frontplate away

It's okay if the power switch and the Start/Select buttons fall out, they always do. Just remember to put them back before re-assembling!

Insert the short part of the Start/Select buttons in the middle first

Then lay the long part into its groove. It should just rest in there, do not press on it at all!