While BIL can be a tremendous asset, please keep in mind that it does not create product listings (also known as ASINs or detail pages), place inventory or check product compliance with applicable laws and regulations across marketplaces, all of which you should have completed prior to enabling your offers for BIL.
To fulfill your North American FBA orders, you will need to ship your inventory to a fulfillment center in the country linked to the marketplace of the order. For example, an Amazon.ca order will only be fulfilled by Amazon from a fulfillment center in Canada. It will not be fulfilled from a fulfillment center in the United States or Mexico.
To fulfill your European FBA orders, you must ship your inventory into a European fulfillment center. For example, a U.K. order can be fulfilled by Amazon from a fulfillment center anywhere in Europe. It will not be fulfilled from a fulfillment center in North America.