You asked so I'ma gonna tell ya, just to help not to screw with ya.
Lst, is best done in the early veg stage, when you first have 3-4 nodes, just tie the bottem of your plant first to the side of the pot, then tie the top of your plant down to a 90 degree angle and so it's all level, I always put the string just behind the last set of fan leafs and poke a hole in the side of my pot and put the string through the hole and tie a not and it holds it in place. And when you do this the plant gives off hormones to make it bush out, and then all the side shoots will grow up to be colas instead of just one. It's not really used too much in flowering except if the plants are getting too tall or uneven, or to open the canopy to get more light to the lower/smaller buds. I hope this helped you some, I'm doing my first lst as well, check out my journal in my sig.
Keep it real........keep it green