First, I would suggest that you do it together - make it a fun, social activity.
Second, start slowly!!! At the end of my
running technique page I have a suggested staged approach for how to start running. Basically do intervals of walking and jogging. Start out with long periods of walking (say 2 minutes) interspersed with short duration of jogging (say 15 seconds). Slowly over the weeks, make the walking periods shorter and the jogging periods longer. Eventually she will be able to jog for the entire duration of the workout but it might take 6 months to build up to that.