They mean schema, not data – using the Import button in the Tables tab of Manage Database.
I'm glad I'm not the only one who was wondering about this. In the email I received, they worded it a little differently, as "Multiple Table Functions" – and I was wondering what exactly they meant by that. I clicked over to the product page that Bruce linked above and saw the text he quoted. I was hoping that meant the ability to import data on multiple tables at once. That would be pretty cool!
They definitely mean the transfer of one or more tables (including fields but without data) from an existing file to an other file.
Using the word "import" here is misleading.
I work with various dbs (including SQLs and FM). I don't recall the ability to do that for any of them.
However, I thought at one time in FMP, a one-one relationship would allow you to import into related fields (perhaps on the layout used for import?). I just don't try to worry about whether this really works and use separate imports.
The "problem" with this is that there may or may not be a key field for relating the data. If you import into parent and auto-enter an ID field, how is that then "imported" into the child table(s) as foreign key? (rhetorical question!!) So, I often create temporary keys that are used to set the correct fields when importing separately.