I honestly just watched a few youtube vids about it, a lot of people said not to top autos because of the stress (i did anyway to see what would happen, topped my only indica so i wouldn't just get 1 bud) Mr. Canucks grow was helpful, but if there's someone u like growing on there they prob have info on it. I waited til they were about 6-7 inches tall, picked a spot under the 1st node, and tied it to a document clip on my fabric pot. If you have experience with topping just pretend that's what you are doing without actually cutting it off. You want to move it out of the way so that the lower branches think it's their time to shine. It's a pretty intuitive process that you will prob match to whatever philosophy you already have about the plants. I think about it like I want to train my dog to do something, shes a genius already, I just have to communicate it in a way that she can understand. With this method you are still convincing the plant that it needs new tops without cutting one off and stressing her out.
My general advice for a first timer because I seem to stumble on all the blocks haha, 1 go slow, you can always do more lst tomorrow (well into flower for some growers) 2 go slow, watch to see how they are reacting (some genetics like it more than others) 3 go slow, when you are tying them down pay attention to the stalk, at the soil so root ball isnt disturbed, and for folding especially in less woody girls (i came back 20 min after 1 session and found the main stalk of my fav patio girl at 90 degree bend, gave her a soft cast with garden ties, shes ok). 4 go whatever speed you want, haha. After a week or 2 its super easy, you will look at ur plant and know where and how you want to train.
All this talk of tying things down and the poor plants don't even get a safe word...