I. download the blender file
II. in the 'layout' workspace set the geometry nodes modifier values
- the seed parameter alters the values of the three extrusions that shape the rock model
- the level parameter defines the steps of subdivision (the lower, the smoother)
* further customisations may be done in the 'geometry nodes' workspace
III. the 'shading' workspace is divided in three areas: rock, moss and mix factor
in the first section it is possible to manipulate
- the scale of the rock texture
- the scale of the displacement texture
- the color palette of the rock texture

in the second section it is possible to manipulate
- the scale of the moss texture
- the color palette of the moss texture

in the third section it is possible to manipulate
- the scale of the moss mask
check the full documentation in the github repository