How to find where someone works

Ask them would be a starter.

You sit out in front of their home and follow them to work?

You ask them where they work ?

You ask people who know them where do they work.

That is all of the "free things: I can think of.

The next question is of course why you want to know.
Trying to garnish their pay, or stalking them

I live in the Bahamas and I need to find where my daughter father works so they can serve the summons on his job and not at his house, how can I found out where he works, I don't have any money for privat investagator.

Then someone follows him to work. You have a chld together. You must know some of his friends and relatives. Ask them.