(How did that happen? I never clicked on 'Answer Now'! To continue anyway . . .)
The instructions you need are here:
https://www.radiocodes.co.uk/ford-radio-code-entry-instructions
If you've really not got the correct code though, a Ford main dealer can get you the code (for a fee) from the vehicle's chassis number. (That, of course, assumes that the radio that's in the car is still the same one that was fitted in the factory). That saves you from possibly having to remove the radio to find its serial number. Around a decade ago, the Ford dealership I worked for was charging £20 for the service.
You might be able to get the serial number by using the instructions in my link. (i.e. press 1 & 6, or 2 & 6, together). That link also tells you how to remove the radio if you end up having to do it.
Once you've got the serial number, there are several online services which can provide the code for a fee.