How do I install a Child theme and get my products to display?

I am getting really confused. I wanted to set up a shopping cart, so I installed the MarketPress plug-in. However, when I installed my theme, I could not see any products. So I installed the FrameMarket theme, and I then could see the product I added, but on the home page it was telling me to use a child theme to get my styling. See below:

“Welcome to the MarketPress parent theme. Please use a child theme to get the styling you require. Any child themes can be found under themes/.
FrameMarket is the parent theme for our MarketPress themes. It allows us to offer a range of themes all using the one core. You also can then use that core to create your own child themes and hit the ground running with creating a MarketPress theme.
Current styles: GridMarket “

When I searched the WordPress site for Child Themes, I found this. http://codex.wordpress.org/Child_Themes
However, it says “In the child theme directory, create a file called style.css. This is the only file required to make a child theme.”

I have read several of the recommended posts. However, I am still lost. In https://premium.wpmudev.org/forums/topic/installing-a-child-theme-over-a-parent-theme it says, “The child theme will have in its own folders a folder titled _inc and within it is a css file - this is where you want to make changes to the theme directly customizing the css as desired but not touching, changing, activating, nor modifying the files in the parent theme that you uploaded earlier.”

I have installed the framemarket theme and moved its child theme, gridmarket, from the framemarket’s own theme folder, but there is no folder titled _inc in ay of the folders of either theme, so the rest of the instructions make no sense. So I wonder, is a child theme coding any different than a regular theme, and how does the parent know which theme is its child?

At http://codex.wordpress.org/Child_Themes it says “In the child theme directory, create a file called style.css. This is the only file required to make a child theme.” Yet in the “gridmarket” folder, there is a whole theme of files. I tried adding the suggested lines to the style.css file in another template to use it, and it looks like this:

“/*
Theme Name: Origin
Description: Origin a child theme for MarketPress
Template: framemarket
Theme URI: http://www.elegantthemes.com/gallery/
Version: 1.9
Description: 2 Column theme from Elegant Themes
Author: Elegant Themes
Author URI: http://www.elegantthemes.com
*/”

But when I tried to activate it, I got the following error message:
“Warning: require_once(/home/content/g/a/d/gadget57ftp/html/x/dollardynamics.com/shop/wp-content/themes/framemarket/epanel/custom_functions.php) [function.require-once]: failed to open stream: No such file or directory in /home/content/g/a/d/gadget57ftp/html/x/dollardynamics.com/shop/wp-content/themes/origin-child/functions.php on line 15

Fatal error: require_once() [function.require]: Failed opening required '/home/content/g/a/d/gadget57ftp/html/x/dollardynamics.com/shop/wp-content/themes/framemarket/epanel/custom_functions.php' (include_path='.:disappointed:usr/local/php5/lib/php') in /home/content/g/a/d/gadget57ftp/html/x/dollardynamics.com/shop/wp-content/themes/origin-child/functions.php on line 15”

So I started getting the above message no matter which theme I try to activate, so I had to re-copy all the original files for all three themes to get it working again. So I decided to try it again with one of your themes, but none of the farms 133 group I looked at had a child theme. That was kind of disappointing. So I tried another one that did. It is called Studio, and I followed the instructions to the letter, copying firs the theme, then the child theme. I activated the child theme and when I look at my store, I see NO products. Obviously I am doing it wrong. I just need some help to get this working right. It says on your site that, “MARKETPRESS ECOMMERCE Works great with any WordPress theme and looks great with AJAXy goodness.” So if I want a different theme how do I get it to work right and to display the products?
Thanks,
Mike