The basic idea of UV-mapping is that you want to put all surfaces of your 3D-model onto a 2D-plane. It can't be done 100% perfect, think of taking a ball and cutting it up and get a flat plane - it can't be done.

However the most basic approach is that you use "Automatic UV mapping" then all parts are arranged and placed for you. You don't have full control of the painting of textures etc however.

For Fur to work the uv:s has to be within the -1,-1 - 1,1 in the uv-map.

So simplest way to get fur:

1. Choose model
2. Create Automatic UV-map
3. Assign Fur

To look at the UV:s open the UV-editor.

Good luck.