The "Bar Chart" widget is very similar to the Pi and 3D Pi widgets in that you can enter the values for each bar as well as their labels as comma separated values.
You will also need to enter:
1. The width and height of the bar
2. The labels of the X axis and Y axis
3. Any text you like for these labels
4. Specify the font sizes for the x axis labels and y axis labels
6. Background colour or transparency
7. Opacity (Optional)
The resultant bar chart will adjust to fill the entire width of the panel and has preset color formatting for the bars.