How to combine multiple objects so adding material affects all objects? I have 5 objects, one parent and 4 children. I used Cube Projection to unwrap and made sure to unwrap all objects at the same time. However when I apply a material from UV Map it only applies the material to one object at a time.

I cannot find a way to apply the UV Map material to all objects all at once. 

What is the most effective way to combine objects to do this?

(Sorry if the answer is obvious, I am an absolute beginner to the software.)
Figured it out - needed to 'Join' all my objects rather than just have them in a family tree.