You can upload large numbers of products for listing on Magento at once using the Bulk Upload functionality in SureDone. You can find information on how to use the Bulk functionality in Section 14. 

For Magento Variation listings, you will want to fill out the product details for each child listing when creating the file. You will also need to create the items in SureDone before pushing to Magento and then relist them once they are added.  

Bulk Header Fields used for Magento

Magento Listing ID. This is how SureDone knows which listing to update on Magento. It is not editable.
Magento SKU. The product SKU in Bigcommerce.
It is not editable.

Magento Categories (ID). These are the numbers that corresponds to the categories this product will display in.
Magento Attribute Set (ID). This is the number that corresponds to the Attribute Set you are assigning to this product, which determines which attributes/fields that are available for the product. Read Magento guide for more information.
Magneto Name (Title). Use this to override the default title on Magento.
Magento Description. Use this field to override the longdescription field.
Magento Short Description. Use this field to override the description field.
Magento Price. Use this to override the default price on Magento.
Magento Tax Class (ID). This is the number that corresponds to the Tax Class that you are assigning to this product.
Magento HTML Title Tag. This is the HTML Title of your product page
Magento Meta Keywords. This is the meta keywords used by search engines.
Magento Metadescription. This is the metadescription used by search engines.