It's confuse because what you say in plural we sometimes say in singular.
For example: "THE CLOTHES that you're wearing..." could be translated both in singular and plural, so: - AS ROUPAS que você está usando... - A ROUPA que você está usando...
Both translations are correct and mean the same.
From my understanding of Spanish, "Roupas" can refer to clothes in general, not just the clothes you are wearing or the ones that are arranged into one outfit. However, I think "roupas" can be used that way.
Example: the clothes in your closet are "roupas" but they aren't ALL part of one outfit. But the clothes in one of your outfits are "roupas..