I’ve learned to add multiple colors to a model, but how do I use more materials such as noise and clouds.
Noise and clouds are “textures” in the materials editor. You can mix them by adding several textures to your material and then set how you want them added to the material (mix, lighten, darken, etc.). Look at the Shading + Materials buttons and Shading + Texture buttons and you’ll see that you have slots to add as many textures as you want.
My problem is I don’t know how to add that to the model.
Here are some useful articles. The first is from the Blender Wiki, the second is from the Blender summer of documentation series.