If you've never done it before, then you are better off going to someone who knows what they are doing
It's not that difficult, you just need to be careful and methodical when doing it.
Try getting hold of a workshop manual, always a good guide and if after reading the appropriate section you feel confident, then give it a go.
Alternatively, find someone you know who can do the job, then watch and learn. Maybe even get them to let you watch when they do someone else's brakes, then get them to supervise you, while you do your own.
Remember, your brakes are the main thing that prevents you denting your P&J, they need to be done correctly.
Let there be light, sound, drums, guitar
LET THERE BE ROCK