There are several ways in which to initiate a call from the Chrome extension.
1. Manual Dialling
With the extension open, click the "home" icon in the left hand corner of the extension window. Type the destination number into the box provided (or copy and paste) then click "Dial". Your handset/soft-phone will start to ring - once you have picked up your handset, the system will connect you to the dialled number.
When a web page is viewed, the extension will automatically detect phone numbers on the page and turn them into clickable links (this can be turned on/off in preferences):
When you click a number, a new window will open as shown below. Click the "Dial" button and your handset or soft-phone should start ringing. Pick up the handset and you will be connected to the selected number.
3. Phone Book
One more option available to make calls is to dial numbers that are stored in your phone book.
Select the phone book from the navigation bar, then click the desired number to initiate a new call to the selected contact.