what does" salt"mean when it is in" Tell me the salt of the story, please"

First notebook entry: Introducing myself Hello everyone! I come from Guilin ,China. I am a outgoing boy and like making friends. I am extremely fond of English. But unfortunately my coyness always curbs the process. I think some of us have encountered the same problem, which can be solved here. well,I'd like to have your acquaintance!!!