...

Categorical attributes that can be used for the Pie chart would display after any data node from the Data card on the left side of the Data Viewer has been clicked. 

Simply drag and drop the attribute, Sample name as an example here, to the Add data in the middle panel (Figure 3).

...

Once you are pleased with the appearance of the dot Pie plot, push Save image button to save it to the local machine. The resulting dialog (Figure 48) controls the resolution of the image file. The image will be saved in your favorite format (.svg format, and the default file name is Dot plot.svg.png and .pdf).

Use the Group order section of the control panel to change the order of the groups on the x-axis. Simply drag and drop a group label to a new position.

...