After receiving the keyboard, we should run the firmware updater, which is available on the SteelSeries website:

During update, we will get to see the progress bar and we should not remove the USB cable from our computer:

SteelSeries Engine is used in order to customize the functionality of the Apex keyboard; the GUI is familiar since we have seen it along with the products tested in the past from the same manufacturer. On the left side we have a list of detected devices, along with the saved profiles, while in the middle we will get to see the menus which are accessible via the top buttons and some custom actions can be defined on the right side. The software programmable layers can be selected from the lower side of the GUI:

The button functions can be redefined by simply pressing with the mouse cursor on one of them and a menu will show on the bottom:

Here is a closer look at the menu we were talking about, which allows button customization:

We can assign a number of different functions from the drop-down menu: