For each layer, you can find Legend settings in the Property Panel. These settings affect custom size, position, and item style. The legend is always shown at the bottom of the page, and under the Position, you can select its alignment to be either left or right (top or bottom settings have not effect).

When you select a chart, the Legend settings that are shown under Appearance, control the shape layer legend.

In the sample screen below, the legend shows the color ranges for the shape.

When you select a chart, the Legend settings that are shown under Other, control the pin layer legend. Each existing pin layer is indexed by a number.