first you need to know for which
Dimension what metric needs to create. From chart, select bar chart type, click next, and select Dimension, click, next, and write the expression. Click finesh.please find the attachment.
emp.qvw 140.8 K
Look at the attach qvw,
It Shows an example of histogrem that shows the distrebution of amont unit solds for number of customers.
I hope it help,
Histogram.qvw 250.0 K