Your best bet would be to ring a few carpenters and get quotes. The cheapest won't always be the best, so ask to look at work they have done, and find out what people think of them.
Above all, try to get an intelligent one. I had a carpenter who could do a great job if everything was straight and level, but once he came up against a problem, all he could see was the problem, couldn't look for, or find a solution.