Static mesh comes up as black square?

I’m trying out UE4 for the first time. I’m trying to modify Tappy Chicken, and as far as I understand, the ‘sprites’ are actually 3D meshes made to look flat.

To start, I wanted to change the logo. I made a 1024x1024px image with some text, saved as .tga, then imported into Blender via the ‘Image As Planes’ addon. I then rotated by 90 degrees on X axis to make it stand upright. Then I exported to .fbx.

Upon importing into Unreal the plane comes up as a black square. Not only that, it’s also tiny! Where have I gone wrong with this?