How do you make Materials allign to Mesh

Hello,
I have made a simple Character in Blender and Baked the Textures. Now i have exported the different Maps aswell as the character Mesh. But when i put the Materials on the Mesh it doesnt allign porperly and you can see the black parts where there was no Material Baked on.

You need to have a better UVW map and unwrap your mesh correctly. Those black spots are the UVs out of the 0-1 space.