Someone please provide me some tutorials for materials that goes from beginner to advance

Hello everyone,
please help me out a bit. I am looking for tutorials of materials that goes from beginner to advance

I want to create a material that is a blend of two/three materials that will not have the repeated tiling in it and will auto generate the different materials based on height of the landscape. So if the landscape is flat then only grass material will show and if there is a slope, the slope will show rocky material.

I have seen some tutorials on youtube but many of them dont remove the issue of tiling

Instead of asking how to do one thing I thought I will ask for a guide that I can use to learn how to do all this. I dont want to copy paste without understanding. So please guys, if you have any resources that might be helpful the please share it with me.