What is the origin of the idiom "not know beans about something" and when to use it?

The origin of the idiom "not know beans about something" can be traced back to early 20th-century American slang. "Beans" in this context is used metaphorically to represent knowledge or expertise, with "not knowing beans" indicating a lack of understanding or familiarity with a particular subject or topic. This idiom is typically used to convey a person's ignorance or incompetence in a specific area.