First Time Dry Hopping

I want to dry hop my American Wheat Extract. I have never tried it before. The beer has been in primary for a little over a week. It is a 4 week kit, so I wasn’t going to rack to secondary. How do I go about putting in the hops? Can I just pull the bung and dump them in? Is there any special cleaning/sanitizing I should do? I don’t want to mess up 5 gallons of beer, so I figured someone with more experience could offer some help. Also, I’m not sure what hops to use. I have an ounce each of citra, cascade and cluster?

Just dump them right in. Id go with an ounce or so of the cascade.