The keyboard is part of the upper case assembly.
Here’s a link to the Service manual for your laptop.
Scroll to p.55 to view the necessary pre-requisite steps and then the procedure to remove the upper case. You have to nearly completely dis-assemble the laptop to get to it.
On p.73-81 Item #2 you will find part numbers (FRU number) for all the various country and colour specific keyboards available for the laptop.
Find the part number appropriate to your particular model (the part number may also be printed on the underside of the upper case if you wish to verify that you have the correct one) and then search online for suppliers of the part by using the part number only in the search term of your browser