You might try looking in local fabric stores or specialty clothing shops. Sometimes, online marketplaces like Amazon or eBay could have what you're looking for.
Well, you could check out department stores in your area. They often have a variety of clothing options, including men's cloth. Also, search on dedicated fashion websites as they might carry the specific brand or style you want.
One option is to visit the official website of Hmung. They might have a list of authorized retailers or offer direct purchasing. Another possibility is to search in large shopping malls that have a diverse range of clothing brands.