It is recommended to place the case on something that will raise it a little (I use the speakers to do this) that will allow the keyboard to fully drop into the slots before screwing anything down. This will make the keyboard sit comfortably and flat to the case at all times.

Place the new keyboard into the casing and start by screwing the screws into where the rivets once were, working from the center outward to get an even fit.

The screws are very small and can easily get lodged inside the keyboard, so a tip is to loosely cover the back of the keyboard with some tape or the like, gently pulling it back when you need to access the hole that is next to be screwed to into.

It is important to occasionally check that no keys are getting stuck when pressed. If this happens then we need to loosen all of the screws so that the keyboard can move a fraction preventing any rub on the case. This is rare as the keyboards are a precise fit. It is a good idea to check on this before to many screws have been secured.

Continue screwing into every position where a rivet once were to make a perfect tightly fitted keyboard that will have zero flex when you are typing on.