Serving parenting time papers?

Hey all, I am working on filing some parenting and custody establishing papers, and after I get a case number for that, I’m filing a motion for temporary parenting time.

The problem is, I don’t know where she went with the kids. I don’t know an address. She won’t tell me. It has been 3 weeks now and she won’t tell me when I can see them. Just ignores it basically. She moved out of my house and took almost everything out of the house.

How do I serve papers without a known address?