ASIO Driver
Turbo Play requires an ASIO driver, which is a low-latency driver that is used by all professional-level sound cards. Turbo Play can use all the sample rates and buffer sizes that your ASIO driver can support. An ASIO driver can have any number of inputs and outputs.

In case you don't have an ASIO driver, you have two options:

Turbo Play can load multiple ASIO drivers, a practise that is not recommended as it will induce unwanted latencies. However, at the Mixer screen you have the option to "Add secondary ASIO driver" from the menu. Once the driver is loaded, you can use an auxilliary mixer to read from/write to this ASIO driver as you would with any other input/output supported by an auxilliary mixer.