Non fiction

[runningpram]

Sorry unsure if this is the right place for this but I've been thinking for a long time about writing a non fiction book.
I've worked in a wordy industry for a long time but embarrassingly have no idea how to even begin with the process of getting a book published.
Can someone tell me whether it's enough to write a plan/synopsis as part of my proposal to an agent or do I always need to write three chapters too? If I've got an idea for a title can I include that? How do non fiction authors find agents - the Writer Yearbook feels a bit hit and miss/random. Are there any other tricks I'm missing?
Sorry, realise these are probably daft questions but would be great to get advice/thoughts.

Non-fiction proposals differ significantly from fiction, tend not to have 'first three chapters' but focus more on the idea and the market. The following link chimes with my experience:
www.janefriedman.com/start-here-how-to-write-a-book-proposal/

Some large publishers accept direct submissions for academic non-fiction (Bloomsbury?). For others, an agent is required or helpful. The process involves finding an agent interested in the 'genre' so similar to finding an appropriate agent for fiction.

Good luck.