Hello,
Regarding your query, actually, to change the background color of the menu, you can add below given CSS following the path Admin Panel > Appearance > Customize > Additional CSS.
.home.menu-sticky #masthead {
background-color: #dddd;
}
You can change the color code as per your requirement.
Further, you can enable/ disable the sticky menu from the instruction link given below.
https://themepalace.com/instructions/themes/travel-master-pro/#doc-how-to-create-a-menu-9
Also, regarding the featured image, please add the image of size 1280*1024 in the banner/slider.
Hope this helps.
If you have further queries, let us know.
Regards.