It is the same procedure for most, if not all, Nikon Cameras.
https://downloadcenter.nikonimglib.com/en/download/fw/524.html
Download the .bin file from the link above to a "firmware" folder and transfer it to the ROOT of the camera's card as described in the instructions. Replace the card if you are using a card reader and go to the Firmware section of Settings and follow the instructions. If you have transferred the .bin file correctly the camera will recognise it and will give you the correct instructions. Make sure that you have a fully charged battery and be prepared for a wait while it loads. There will be a (slow) progress bar.
DG
You will need to open the "updating the camera firmware" link.