If you've not got that much mechanical knowledge then it's probably best to leave it to a proffesional

You could find a local pf type to help you out but on mine it took about 2 hours from start to finish and I didn't know what I was doing before I started

It is fairly straight forward it's just really really awkward as gaining access to the bits is very difficult

The biggest thing is not breaking the trim when you remove it, I broke mine in two places so if you can get that off the rest should be plain sailing