Create virtual recording devices in WireTap Anywhere by clicking on the plus button. Click on Settings to configure the device.
To record with that device, simply select it in the input menu of your favorite recording software and record as usual!
For more complete instructions, open WireTap Anywhere and click on the question mark button in the lower right to open the WireTap Anywhere Help. Creating virtual devices is explained in the section called Using WireTap Anywhere Virtual Devices.