Here is a very basic video on how to dry hop your newly brewed beer. Typically I will start the dry hop 3-4 days after primary fermentation has started. This will allow the yeast to help keep things clean. Depending on the beer I will leave the dry hops in for up to 10 days. But that is really up to you. In this case I dry hopped in the primary fermenter but if you wanted to you could also do it in the secondary. If you have any questions feel free to ask.