Once you have your Sangoma Talk app configured on your phone, you can then add Quick Dials to make it easier to transfer calls, check voicemail, park calls and check users availability. 

You will need to click on Quick Dials on the bottom of the app. 

Next you will click on the plus on the bottom right. 

You will then need to fill in the box with what you would like the quick dial to be. For an extension it will be the main number for your company and the extension (all together), parking slots and voicemail, you will need to contact support by emailing or calling (phonepro@mercury.net or 9898373790 extension 12).