Hello, @ericleestudio,
1.. Actually, that is a promo for the XStore theme sale it’s not a part of demo content so you cannot add it.
2.. Simply remove the widgets from the header you want no need to worry about it all the widgets are available in the header builder to see image: https://postimg.cc/sBMfkKrh
3.. Go to the Dashboard >> XSTORE >> Theme Options >> Theme Custom CSS and then paste the below code there.
.product-view-default .footer-product .show-quickly{background:red !important;}
Then save settings and check back to your site after clearing the browser cache.
Note: In the above code the word red is the color you can change it with you want.
Regards 8Themes Team.