Normally, I'll lay the board in the water in front of me, then I rest my heels on top of the deck, in whatever position I want to be standing in. Have the driver nudge the boat into gear, and as you get some line tension, press down with your heels. This will pop the board on its edge in the water, and hold it against your feet. Then its just like getting up on a wakeboard.
Some people will also just hold the board with one hand, rope in the other, until the driver puts some tension on the line, and its all the same from there.