Hello,

01. Please use the Header “Overlap Option” Navigate to Woodmart > Header builder > edit current header in the header setting enable the option to make it overlap.
https://monosnap.com/file/mgQnNv4DPOZwNeaYYsYPTan0zPd6Zb

You do not need to set the background color if you want to make overlap. Please add this code to the Theme Settings > Custom CSS > Global for sticky header background.

body .whb-sticked .whb-general-header, .whb-sticky-shadow.whb-sticked .whb-row:last-child {
    background: orange !important;
}

02. Please follow this guide and set up it.
https://xtemos.com/docs-topic/how-to-create-a-slider/

Best Regards