#1. First, install Squarespace ID finder to find the ID of the List Carousel.
In my example, we will have:
section[data-section-id="660e4648139aa96bf669b3ae"]

#2. Use this code to Custom CSS box
section[data-section-id="660e4648139aa96bf669b3ae"] {
.user-items-list {
display: flex;
flex-direction: row;
}
div.list-section-title {
margin: 0px !important;
flex: 0 0 20%;
padding: 0px !important;
}
.user-items-list-item-container.user-items-list-carousel {
flex: 1 0 70%;
}}

#3. Result
