lyx contents page numbering

The following is quoted from  https://wiki.lyx.org/FAQ/Numbering#startpage

How can I have roman pagination (i, ii, iii...) for the first part of my document?

• If you use a book class, simply insert
  \frontmatter
  at the beginning of the document. This will switch page numbering to roman (i, ii, iii...)
  \mainmatter
  will switch back to arabic (1, 2, ...) and start from "1".
• With report or article classes, insert at the beginning (in the LaTeX preamble):
  \pagenumbering{roman}
  and then, where you want to switch back (somewhere on the page in the normal text), in ERT (Ctrl-L):
  \pagenumbering{arabic}
  \setcounter{page}{1}

My LyX example: