The Extension usage report will give you a breakdown of the amount of inbound/outbound calls made by the agents/extensions on your account & a breakdown of the duration of these calls made

Date & Time Range

You can pull the report from a specific Date or range of dates
after you have made your selection, press Apply

Additional Report Options

you can apply the following filters when looking at the report

Extension Usage

(to view a larger image, right click on the image and open in new tab)

by moving the mouse over a line, you will get a further breakdown of the calls for that extension

Inbound/Outbound total call duration

(to view a larger image, right click on the image and open in new tab)

by moving the mouse over a line, you will get a further breakdown of the calls for that extension

if you wish, you can also get details of the report in a CSV file, by clicking the Export CSV button