Go to "Product Upload" under the menu "DataFeed Manager" and click to the button "Add New Import Task".
There click to the plus sign and choose "GOOGLE DOCS URL" from the scroll-down menu of "Connection type" and click to "Save".
There you will need to paste the link of the Google Sheet and choose the file type.
Click to "Upload" and in the "Settings" part choose the "Sheet" and click to "Save" there as well:
Then you will be able to start doing the mapping.
If you need any assistance regarding these steps, please do not hesitate to contact us.