 So you know how to make automaterials and you know where the infinite textures are, but you don't know how to combine them, not a problem. Assuming you followed my automaterial tutorial, you will have two material functions. One for grass and one for dirt or stone. Obviously we're not going to need these maps, so we can go ahead and delete them, open the infinite non-repeating texture you like for the grass, copy it, then go to your grass function and paste it right in. Connect the base color, roughness and normal, then do the exact same thing for the dirt texture. Find the one you like, open the function, copy, paste, drag the color, drag the roughness, and the normal. You're done. I hope that helps and as always I hope you have a fantastic day and I'll see you around.