Scrolling Navigation for single page site

Site URL: https://lenexis-foodworks.squarespace.com/

site pw: lenexis

How do I create navigation tabs for each individual section of the homepage so that clicking on the navigation title would make the homepage jump to that section?  like https://cartesianconsulting.com/

Also how do I remove the shadow from the "Rolls n Bowls" and "The Momo Co." images? These are transparent pngs but there is a shadow around both which I don't understand.

Would appreciate it if someone could help with both these points. Thank you.

#1. Use anchor links

https://support.squarespace.com/hc/en-us/articles/207135178-Creating-anchor-links

#2. Add to Design > Custom CSS

div#block-3442c601f50060b98689, div#block-1023baa3c598a5488b48 {
.image-overlay {
    background-color: transparent !important;
}}

@tuanphanThank you so much. Both your inputs helped! :))