With material displacement you can create details, bumps and other surface information onto your model with a grayscale image called a height map. When creating or using existing height map, take a note that the black/darger areas are lowered and white/lighter areas are raised.
If you want to use your height map in Stager, go to the Properties panel → Material → Height section where you apply the height map, then go to Object tab → enable displacement.
Height map is a grayscale image which sets the surface information onto your model.
Height map options
Next thing to do is adjust your height scale/level.
Normally I only adjust the scale, and leave level to 0.5, more information about the height level on Adobe's Documentation page.
Height scale represents the distance of the displacement, so in plain language the higher value will set the displacement/reach of the height more further away from the object.
Displacement tessellation options
Once you're in the Object/Displacement panel, you need to enable Displacement and decide which Tesselation mode you want to use. I've been mainly working with per-triangle-fixed mode, here's a take from Adobe's documentation explaining the tesselation modes:
Tessellation is a system which takes the original shape of the model and adds more geometry detail to it. Displacement works by offsetting the geometry surface, so if the model doesn't have enough detail the displacement effect can appear coarse with artifacts and stretching.
Uniform (per-triangle fixed) will equally take every triangle on the underlying model and split it into new face. Each subdivision will increase the number of faces again.
Uniform (total face budget) will also equally divide faces, but will stop once a maximum number of faces are created.
As you can see, higher the per-triangle fixed subdivision value is, more detail you can get. But since each subdivision will increase the number of faces, the more your PC will use resources and your scene can get quite heavy so start adjusting it from lower values at first and see how high you can get.