Thank you for the reply.
My horizontal bar chart has y-axis (dimension) username, x-axis (measure) login count.
Under appearance => Y-axis => Position, I can see 2 options that can make the usernames show up either on the left side of the bar or on the right side of the corresponding bar.
I need the username to be above the corresponding bar instead.
My real question is for customizations like this, which are not available in the default bar chart, is it possible for me to add my custom code to these add additional behaviours.