Fortnite - style challenges?

As I've heard and seen, certain styles can be unlocked for some things from the Battlepass.

For example with the sign that I attached as a picture. You can also unlock this shield in a yellow version. However, I don't know what to do for it? Nothing is shown in the challenges where I get this variant.

Then you can't unlock anything

It's important to learn to read before you try to answer questions.