Using the browser version of the Bungie website, log into your acct. Then, find the spot where your clans can be viewed and tap on the clan name itself. This should bring up the clan's site and show a couple of options in the Bottom left corner of the large banner with the clan's name. Find the option to "Set as your clan" and select it. This should allow to appear on your emblem in game and also unlock the ability to earn certain Playstation trophies (like Xbox achievements). Another way to find your clan is to google the clan name along with Bungie.net. It should provide a direct link to their site. As long as you're signed in already, use that link and find the option to set them as your clan. Hope it all works out.