Facebook is easy. Break off Instagram and WhatsApp. Those acquisitions should never have been allowed. Amazon might look like splitting retail from AWS or similar.
Breaking Amazon apart into a retail business and a cloud computing business to address monopoly concerns is about the most pointless idea possible. If you think that Amazon exerts a monopoly influence over retail and cloud computing, splitting off AWS does nothing to address that.
Eliminate the self-dealing by cleaving the advertising marketplaces from their other businesses. They can still show ads. They just wouldn't be able to run the auctions, exchanges, etc.