2. Clone the sphere and name the new sphere as “cloud”. Make it slightly big as shown below.
3. Open material editor. Put materials as below

Materials for cloud and earth
Way to put for earth`s material
Way to put for clouds material
If you render now you can see your earth like this.

Now select perspective viewport and make a camera there .
You can animate your earth. Click Autokey to ON it
To add stars open video post from render menu. Click this button
4. Now click this button
5. Click this button
6. Click this button
Your earth is ready.