Sound Activated Recording

I am using Vista 32 Bit, and Audacity 2.0.
How do I use the Sound Activated Recording facility. I have ticked the item in the drop down box under Transport, but do not know what to do next.
Many thanks,

Did you verify that you could record successfully using the normal “Record” button to start and “Stop” button to stop technique? There’s no point trying to get Sound Activated recording working if the basic recording isn’t working properly.

When you have confirmed that “normal” recording (Sound Activated recording disable) works as expected, enable Sound Activated recording and press the Record button. When the input is over the specified level Audacity will record and if the input is below the specified level Audacity will pause the recording. If recording is continuous then you have set the level too low. If Audacity is constantly paused and does not record then either your input signal is too low or the activation level is set too high.

Thanks so much. Works like a charm!