Having fitted this kit twice, once on a 6 and once on a CX-3, I thought I'd just try and offer a little helpful info. I can definitely say that this job can be a right pita! To make life easier get yourself a set of the soft plastic trim removal tools and a set of electrical connector removal tools (look on Amazon for "Auto Terminals Removal Tool Set,Car Electrical Wiring Crimp Connector Pin Extractor Kit for Car Repair")
The instructions are as clear as mud when it comes to removing the 2 screws. To access the screw behind the door release lever, you will need to carefully pry out a small piece of plastic trim thats sat just behind the silver lever. To remove the window and mirror switch panel, you need to remove a larger section using the trim tools than the instructions show.
Remove the screw behind there and remove the door panel.
Here's where the fun begins! The first time I did this job I didn't have the set of connector removal tools, and it took me forever to remove the pins from the blocks, I almost sacked the whole thing off a couple of times. Using the tool that is 1.5mm wide and 0.5mm thick insert it as shown, this will allow the connector to be pulled out the back of the block.
Inserting the pins is pretty straightforward. To remove the pin from the door lock connector, insert the tool from the rear of the block. (When the instructions mention option 1 and 2 for the double locking system, this isn't a question of what you want, your car will be already wired the same as option 1 or 2 that's all, depending on the position of the Yellow Brown wire)
Make sure that all the connectors are firmly pushed in when finishing, I didn't and had that sinking feeling when I tested it all and it didn't work. Overall like I said not a fun job, and really don't attempt it unless you have the tool or similar. HTH somebody.