Take a look at legallyflying's journal as well as the tutorials in this thread by woodsmantoker, I have some pics I can post that should help but have to fly right this sec, will try to get back to it this evening. Generally speaking you want to train the stems to the screen positioning a bud site about every 2" or so. There are different techniques, some allow them to grow 3"-4" above the screen then pull them back under, some train them under or over the screen and tie them w/ plastic twistys, some use a spiral pattern out from the center, others use a back & forth pattern. The goal is to completely fill your screen with evenly distributed bud sites just about the time they complete the "stretch" after flipping to 12/12. Hope that helps, I'll get those pics up as soon as I can.