There are a few methods you can use to promote branching and one of those is topping your plant. After you pinch the top of your plant, you´ll have to wait for the plant to heal and soon you´ll see the results. Maybe topping is not the best method for this cause, but it´s quite simple and effective. You just have to wait while they heal and soon you´ll have a little bush. I have just done some topping a few days ago, so take a look at this sweet little example.