header-image (masthead) with parallax effect?

Hello all,

i have been looking for a way to only use a parallax effect only for the header-image or to get a similar effect on top of the page.

in the js folder there is a scrolly.js but even when using page builder> row> siteorigin image> background-image> design: parallax(full), i still don’t any effect happen on page.

is there something I am missing? how have others done it with this theme?

I use the free theme on 4.3 with a child-theme but haven’t adjusted anything yet.

much obliged!