Urgent Help - Ford CD player install?

[BRISTOL86]

Hi guys

I have a 2007 fiesta which I had an aftermarket head unit fitted into (professionally)

I'm selling the car and now want to put the standard ford 6000cd stereo back in.

Is this something I can do myself? I don't want to bugger anything up, should I just take it to a pro? I have no idea what I'm expecting to see if I take the old unit out myself!

Thanks in advance