It depends. You can do it however you want to. You could top first and then use the two shoots to go opposite directions around the pot. This way you complete the circle sooner. Then, once you have your circle, you can top the shoots that grow upwards, splitting each into two colas. You have to be careful with excessive training, though. First, because you don't want to add alot of time to the process. Secondly, the root system and main stem can only transport so many nutrients at a time. As you try to make more colas, you eventually get to the point where the stem is a bottleneck and each new cola only decreases the size of all the others. Most strains we've tried reach this point at about 6 colas. The main stem gets thicker with age so older plants can generally grow more than younger ones of similar size.