Problem with Custom Parkour Wall Texture in Fortnite...

Hello,

I’m reaching out because I recently came across a parkour map on Fortnite, and I found the wall and floor textures really beautiful. I tried to recreate them by adding a texture with a black outline.
However, when I apply it to the same wall used in the map, I don’t get the same result at all.

I really need this texture to work with that wall for my parkour maps. Could you please help me understand what might be going wrong?

Thank you in advance!