I don't know how to ask her out

There's this girl who works as a waitress at a very fancy restaurant that I went a couple of times, and I really like her. She acts very professionally and I have never got a sign that she's into me or whatever. But I want to politely ask her out and I genuinely don't know how to do it. I'm a shy person and I've never asked someone out. Please help me, it's bothering me. And please try to guide me with some examples.