Configuring Custom Dial Plan to a Phone Number
Login in your Account Portal, Click on Phone Numbers. Select the number you want to configure to set up call forwarding..
List of Phone Numbers
Click on any number and select "Edit Configuration" to go to configuration screen.
Select Custom Dial Plan and select the Call Flow that you have previously created an would like to apply from the list.
Click on Save.
There are lot or advanced options, Click on the "?" to see the description for each option.