How can I add custom material to my Landscape TargetLayer list?

Hi I wanted to find out how can I add my custom material to my Landscape TargetLayer list ? I did this before, and it was long time ago, but I cannot really recall my memory - how ?

As far as I remember this: I used the No-weight-blend layer info type.

I mean: I created ( for example ) mywood_01_mat, that I want to use to paint my landscape, what do I need to do ?

Okay - I managed to add custom materials by opening the Landscape_Material instance and replacing the default Dirt Grass and Snow solid color textures with my own textures, then I selected the “non-weight blend”. Now I need to reduce the shine intensity because the terrain currently is too shiny. I have set the roughness to 0.9, but the land is still too shiny… Can somebody tell me how can I assign the normal map to a specyfic grass texture, that belongs to my custom Landscape_Material ? What node do I need to use ?

I am still wainting for help, please.