Each campaign you have has it's own recording rules.  You can force recording of every call, allow the agents to start and stop recording at any time or not record calls at all.  

To get started, click on the tab Call Center and then, Campaigns.

In Show Campaigns, click on Action button and select Settings from the drop down.

Under General tab, scroll down to Call Recording and select the Recording option you wish to apply to the Campaign.

 The four options available are:

• NEVER: No calls will be recorded.
• ON DEMAND: This setting allows the agent to choose when to start or stop the recording using the recording button (Start Recording) on their interface.
• ALLCALLS: This will initiate recording at the beginning of all calls, but will allow the agent to stop the recording if needed.
• ALLFORCE: This will record all calls.  The agent cannot start or stop recordings in this mode.

After selecting the option needed, click on Apply Changes button.