After drag-and-drop tile to dashboard, click to edit tile (Pen icon), choose dashboard title and select or create analysis/query that will feed current tile with data we like to visualize.
Essentially, each dashboard tile is receiving data in the format of categories and series. Column and line charts could accept many series of values, list chart accepts one or two series of values, while Pie chart, KPI and Gauge meter accepts only one series of values to visualize data.