How do I set up a ShareASale data feed?

From My Account > Add Feed, create a ShareASale feed for your store and configure the settings. Leave the FTP Username, Password, and Server at their default values for now.
From Manage > Define Fields, edit the Merchant ID field and enter your ShareASale Merchant ID in the Value box. You can obtain your Merchant ID by logging into your ShareASale account and looking in the header of the page.
From Manage > Define Fields, edit the Category and Sub-category fields (not Merchant Category). Look up the appropriate number from the ShareASale data feed file format specification, and enter it in the Default Value box. You must supply both the category number and sub-category number.
For example:
Category: DefaultValue = 6, CatalogField = blank
Subcategory: DefaultValue = 47, CatalogField = blank
If you have multiple categories of products, add a custom field to your store catalog and populate it with the category numbers. Enter the name of this custom field in the Catalog Field box.