I understand how to get heightmaps in to WED. But I am uncertain as to how to get textures in.

From the A7 manual
Quickstart: Open the tool under Tools / Terrain / Texture Creator. In the [Source Tex] mode, click Add Texture: [Z-Axis] and open grass.tga in the templates_6\images folder. Repeat this with sand.tga and rock.tga. When toggling through the 3 textures ([Up] / [Down] arrows), you'll see the texture height levels marked red in the terrain wireframe image.

So that means I can only have one grass and one rock and one sand texture? That is going to be a very boring landscape. I must be misunderstanding something.

I have A7 commercial.