Data feeds are a convenient way to create multiple items in Google Merchant Center. Feeds are assigned an item type, which classifies the feed according to what sort of items it contains. Once you've created your file, you'll upload it to Google. After your file is processed, your items will be added to Google. Creating and submitting your feed can be done in just four steps:

Data feed File Name is the file name you want to use. The settings we suggest require it to be a .TXT extension

1. FTP User -  is the username you use to login to Merchant Feed.
2. FTP Password  - is the password you use to login to Merchant Feed.
3. Google FTP -  is the ftp url for Google's servers (should be ftp://uploads.google.com).

For your convenience, by default, the generated feed will filter out products that not have the necessary required attributes, according to Google's Products Feed Specification's. This "filter" is to be considered a best attempt and is in no way a guarantee that the feed generated will pass Google's requirements.

Select the "Ignore Attribute Requirements" option prior to generating the feed to disable our "filter" that removes the products that do not have the attributes you need to provide in order for your products to be listed in Google Product Search.

Important: Regardless of your selections, this feed only selects products that are available for purchase (ignoring products that are not active or out of stock with the proper inventory settings.

For Specific guidelines, please refer to Google's documentation: http://support.google.com/merchants/bin/answer.py?hl=en&answer=1344057

Location

After your feed is finished generating, your data feed file will be placed in your store's "FILES/FEEDS" directory.

Now, you will want to create/register the a data feed within your Google Merchant Center.

Here is more help with this from Google: Register a data feed

Several Additional columns can be included in the Google Merchant Feed.  Below is a list of all the columns that can be output with the Feed and where the data comes from in 7cart.

Any values that are not "standard" should be imported using product type properties. For example: "<producttypeproperty name="google_custom_label_0" />"