[Noob] Help with landscape textures

All the questions I am asking are underlined, (the help I need)

Hello, I am very new to Unreal and have only used Unity very mildly. My knowledge is pretty limited but I am definitely willing to learn about the more advanced techniques. I know I shouldn’t dive straight in, but this is my preference for learning. So if there is something extremely complicated but will still help/improve that you usually wouldn’t try to explain to a beginner, please share.

I am currently trying to make a horror game. I wont bore you with details, only explain what you will need to know if you would like to help.
It is at night
It is going to be raining
It is on a paranormal, isolated island surrounded by ocean.

The island consists of 3 parts. An octagon, and two larger rectangular like shapes

In this thread I am focusing on the octagon. I would not like it to look so man made, with the material on the slopes of the octagon. I think the best way to recreate it is to just simply make a circular terrain and use the erosion brush on the slopes, making it look a bit more realistic. Is there a better way to do this?

The only problem I have is with the material. I would like it to be quite realistic but I am not sure how to achieve this look. During my time with Unity, I used the diffuse & normal map to make a material but it didn’t look very good. I have tried to find a tutorial on making a good ground material but all the videos I have watched just show how to use a normal & diffuse map. My original plan was just to create some dirt and grass texture blended together (like the image above) but I quickly realised I wanted something a bit more interesting. I have decided to go with more of an eerie, isolated feeling to fit the rest of the game. (Heavy rain, wind, strong tide and scary atmosphere.) Instead I am going to try to use dead leaves, dead grass, dirt and rocks on the ground. Also a hard dirt/rock material for the slopes of the island. I cant find any good pictures to try to explain my idea.

Everything would be wet because of its raining constantly. How would I go about creating everything? I am not sure of how to make any of the materials I would like. If I find a good diffuse map, then make a normal map, AO map & Specular map for the dirt where do I go from there?

I think for the grass I am going to use this blueprint pack which I can just customize Unreal Engine 4 - Advanced Cinematic Grass Blueprint *FREE ASSETS* (Updated: 5/6/2020) - YouTube.
I will also find an asset for rocks

But for the leaves I also cannot find any tutorials. I would like the leaves to move as if there was wind, as the scene has heavy rain & strong winds. I have tried to find a tutorial for this, where there are dead leaves on the floor which get pushed, so it looks like wind. I have only found dead leaves textures which I could paint on to the landscape. Is there anyway to do this or should I just find a good texture, and make it a realistic material by adding all the maps?

I realise this is a bit long, so thanks for anyone who took their time to read this!

As noted in another thread, I have moved your thread to Content Creation. Maybe you will get more responses.

It also might be more beneficial to break your question down a bit more and not just throw out a wall of text.

All your questions are already answered within the huge example content from EPIC which was, is and will be available to anyone who is using UE.
You can find it here: Content by Epic - UE Marketplace Games

Altogether it shows the best way of how to create and use terrain, effects, landscapes in general, materials and blueprints
The rest is just practise.

Also by typing “Unreal Engine Advanced Material” in either witchcraft search engine “Google” or “Youtube” will bring forth magical results:

Your problem isn’t Unreal4, as you mentioned you used Unity before and just put a normal map and a diffuse in the standard shader. You need to learn how the different textures work in a shader/any game engine. Wetness reflects, looks shiny, so it for sure needs a specular texture. Combine it with a roughness texture. I understand why you don’t know about this, the Unity engine doesn’t allow you to create custom materials easily, you gotta run with the U5 shader or start learning how to code shaders. In UE4 just create a new material and experiment with the textures, you also have many content examples that can help you creating the look you are trying to get.