Register supplemental feed file in Google Merchant Center
Log in to your Google Merchant Center. Make sure you have administrative rights.
From the main menu to the left, select Products -> Feeds:
Click Add supplemental feed:
Name your feed and choose an input method. You can use any name, we suggest to choose Upload as input method:
Enter the name of the file you have created before, containing Auto Pricing Min Price values (if you use the file created in your emarketing account the file name is products.csv)
Click Upload a file now (optional):
Select your file from your computer’s file system.
Select your main product feed and target country, click Create feed:
Google Merchant Center will now process your upload and generate a report. If product IDs from your supplemental feed file match those of your main product feed, values for Auto Pricing Min Price will be added to the products of your main product feed.