In the same way we need to look at the world and realize there MUST be an overall designer who decided to create the universe and build each individual thing. The creator is G-d, who not only created everything but created each thing with love, though and design - including every person and every child.
The book continues, laying out each law in simple terms and showing how following the law leads to a safe and just society. The book finishes with a description of what will happen when people accept G-d as both the one who created and sustains the world - and then choose to follow his laws for mankind.
The book is written in simple to understand poetry, in the style, level and complexity of the young children it's written for.