Jobs at small Dallas companies nobody posts about

A friend who works at a local manufacturer says there are openings not advertised online. There are 8 people counting on me, so I am trying to be careful. They prefer people who can start within a couple of weeks. What do you write in a cold email?

Thanks for writing this out. I went through something close to it 14 months ago, and it got easier once I kept a simple log of every call and form.