We have many customers who have an IDX Broker account who have an API Key for it. For those people, they can auto-populate listing information into the Property that way. To learn more click here.
Other than that we have no function to import listings from any other source. We will be adding more IDX providers as we go but that's it for the foreseeable future.
NOTE: In Settings, Boards
NOTE: In the Property itself, MLS information is only informational unless you are using IDX Broker.
To add an MLS Number, click on the Listing Tab, and then Add New.