Can't Add Textures Over Terrain - 2018.3.0f2 Personal MacOS

Hey everyone! I am a beginner with Unity and I've been trying to add a texture over my terrain but it seems as the button to edit textures is missing or my version (2018.3.0f2 Personal MacOS) is different to other peoples.

When I go into Inspector > Terrain > "Paintbrush" > Paint Texture, the button "Edit Textures" does not appear as shown in all the tutorials I've seen. I have no idea what I need to do or if there is even another way to add a texture over my terrain. (See images)

Sorry if this is a silly question but I am a beginner with Unity.
Thanks everyone!

Images: https://drive.google.com/drive/folders/1b-XlzbUvLlLLW35hhh_tp9pBOI0NE3G7?usp=sharing

 

Hi,
maybe the tutorials are not up to date, because the terrain tools are heavily overhauled.
On your screenshot you will see the "edit terrain layers" button. Click it and you get more choices e.g. "add terrain layer". Then add a new terrain layer and a texture to the new layer. Now you can paint the terrain.

 

Thanks a lot that’s correct.