It's all up to you. For a one-plant grow, you will want to maximize flowering tops. You'll want to place a ScrOG net to spread the tops out at all the same height. You can top anywhere you need to top until you have enough bud sites to fill the grow space then flip to flower. Depending on where you are in veg, you could try to use the manifolding technique to create eight main branches. Check out the tutorials on the main site for ways to maximize flower production.