change # links in one page version

Hello
how to change the links in the # OnePage version of wordpress theme?
EXAMPLE: # gk-header for portfolio
(creativity)

Hi, check Dashboard -> Appearance -> Menus -> FrontPage Mainmenu, here you can change URLs of the links.

#gk-header is a link to Header widget position, you can use other positions e.g. #gk-bottom1, #gk-bottom2..

Thanks a lot for your reply
By cons, I would change the names of links
exemple : chaneg #gk-bottom1 in #customname
where can I get it?
thanks again

Like I said you have to change URLs (or Navigation Label if you want to change names of the links).

if you changed #gk-bottom1 to #customname you must have #customname (Anchor Link) on your curent page.
#gk-bottom1, #gk-header etc are id's of widget positions (HTML structure).
Read this article.
You can create anchor links e.g. on text widgets.