A substance archive (.sbsar) is an exported graph from Substance Designer.
This means that it contains a material that can be adjusted using predefined sliders that have been set by it’s author. You can use it to create your own variations of a material found on CC0 Textures.
Plugins for 3DS Max, Maya, Modo, Houdini, Unity, Unreal Engine and many other tools can be found on the Substance Website.
If you are working with a program that has no built-in (or plugin-based) substance support like Blender, you can use the free Substance Player software from the Substance Website.
Once you have downloaded the Substance Player you can install it like any other program. Run it and open the .sbsar file. You will then find a number of sliders to your right hand side. To your left you will see a 2D and 3D Preview. Adjust your settings until the material appeals to your needs. Then click on “Export as Bitmaps” in the top left corner.