Understanding a bit about resolution resolver - libgdx

Understanding a bit about resolution resolver - libgdx

i have been reading most of the questions and trying to understand the
solution but im still confused on how to make it work.
i made 3 atlases for different resolutions and currently im on a roadblock
in these codes :
Resolution[] resolutions = {new Resolution(320, 480, ".320480"), new
Resolution(480, 800, ".480800"),
new Resolution(480, 856, ".480854")};
// do i need to make folders with resolution like 320480/foo.jpg or make
an image named like foo.jpg.320480 *correct me if im wrong... im really
confused here so please bear with me
// what does this code do?
Texture.setAssetManager(ass_manager);
really needed for me to lean to make the screen not look ugly.
much appreciated, Dvd