Plant them in a pot as you would other seeds. I recently planted some yucca myself, the sprout pretty quickly, water well to germinate then when the plant gets about 2-3 inches let the top of the soil get a bit dry before watering again. Let the yucca establish good strong roots before you replant into your yard, when you replant give it the normal amount of water, about once a month or once every two weeks if no monoons have hit.