Go to Navigation Menu on the right of the screen and choose the 'Management' tab.
Then select 'Zones & Rates'.
A list of all your current zones will populate
Choose 'Manage Rates' in blue
If there are rates, you will see a list of current rates
If there are no rates you will have the choice to create a rate
At this point you will have to choose what type of rates you are going to use.
Here is a breakdown of rates options to use.
If you want to create an on-demand rate you can view this article for more information.