How can I change the number of displayed items in the carousel?

You can define this in the RecolizeParameters JavaScript object in your domain’s advanced configuration under “Add additional JavaScript code to execute before Recolize initialization”:

RecolizeParameters.Position = {
    1: {
        Carousel: {
            responsive: {
                668: {
                    items: 3
                }
            }
        }
    },
    2: {
        Carousel: {
            responsive: {
                668: {
                    items: 3
                }
            }
        }
    },
    3: {
        Carousel: {
            responsive: {
                668: {
                    items: 3
                }
            }
        }
    }
}

1, 2 and 3 are the positions. If you need more positions per page, then just define more position objects.

The standard responsive breakpoints are:

0: {
    items: 2
},
360: {
    items: 3
},
668: {
    items: 4
}