Show sublevel and hyphen sign

I have a Writer Documnetation. It contains of TOC. each Level contain a sub-level. I need to put 1-1 for sub-level or 1-2 or 1-3 and so on.
But my TO‌C‌ doesn’t show hyphen sign and sub-level number.
My OS is : GNU\Linux
My libre version is: 7.3

Please, edit your question (= modify it, don’t use a comment) to add technical information: OS name, LO version and save format (.odt or .doc(x)). For best advice attach a 1- or 2-page sample document.

Numbering scheme for headings and TOC is customised in Tools>Chapter Numbering.