I copied this from howtowakesurf.com:
Put the board in front of you. Lay back and put your feet on top of the board; the board will be floating on top of the water. Hold the rope and then signal the driver when you are ready. As soon as the boat start moving, push down with the heels of your feet so the board flips up flat against your feet. Once the board is flat under your feet, stand slowly.
My wife Judy has difficulty with larger boards, she is so petite, so we have to do what we call "faster, slower"
Once she is ready I engage the transmission and start moving forward slowly while she pushes down with her heels. The movement through the water, slowly, will eventually flip the board up against her feet. Once I see the board up against her feet I can accelerate normally.
The key, for her, is just to get the leading rail out of the water and the pressure of the water, as we move forward, slowly, will eventually flip the board up against her feet.