You can assign the keyboard key to the mouse key using our OP software.
Download the software from our website https://fnatic.com/gear/op then start the OP and select the option to customize your mouse, then go to Key bindings and click on the desired button, choose Action Keyboard Macro. then click on Choose macro/New macro, then Start recording and save the action/key from your keyboard which you want to assign.
To customize colors for individual key, you should use OP software and the option Lightning - Color Editor.
To save different color on each key, you need to click on Add group, click on the desired button and set up the color that you want using the color wheel.