@Oka You must select an ASIO driver in the program settings under the File menu > Settings > Program Settings > Audio/MIDI.
Usually, you select the ASIO driver of your audio interface. I'm not sure if your Audio Mixer comes with one. Music Maker has a generic Music Maker ASIO driver. You can try it. Next, click on the Advanced button to open the driver settings. Select your audio input and audio output and set the buffer size to something reasonable like 512 samples.