Assistance With Unstacking a Bar Chart

[#1]

I think this is a simple question. I am importing 3 fields from another database (savings potential low, savings potential target, and savings potential stretch). I am creating a bar chart and selecting these as dimensions. Then for each of these I am making an expression (i.e. sum(savings potential low). When I run the chart, these three items are stacking into one bar. I want them to be separate comparative bars. Can someone please assist?