We talked a bit about the best way to make it - how big it should be, what colors we should use, etc. He chose which phrases he wanted to use. I cut and stained the boards, just for the sake of time (so they could dry before he arrived to work on the rest of it). We attached the boards together using two eight-inch mending plates. I drilled the first pilot hole, then let him do the rest, including screwing the mending plates into the wood. He stamped the letters and filled them in a bit where he needed to, then signed this name on the back.
Katie wrote a great write-up of the whole thing here: Mother's Day.