Child Theme problems

You are on the right track
First off.
Start with a css file.

/*
Theme Name: 
Theme URI: 
Description: 
Author: 
Author URI:
Version:
Template: 
*/
@import url("../{theme_name}/style.css");

If you overwrite styles:
Only write the classes and ids you want to overwrite and end them with an !important
for example:

.container{
    margin:0 0 0 50px !important;
}

Only copy the files you want to overwrite, not the entire theme.
Create a functions.php in your child-theme folder and enqueue the child theme css file

Function wp_enqueue_scripts() {
    wp_register_style( 'childstyle', get_stylesheet_directory_uri() . '/style.css'  );
    wp_enqueue_style( 'childstyle' );
}
add_action( 'wp_enqueue_scripts', 'wp_enqueue_scripts', 11);

This should get you going….