One way to reduce latency on monitoring (which is what I assume you're talking about?) is to go to Studio One > Options > Audio Setup and then change "Device Block Size" to a lower number of samples. Depending on your hardware, you may experience more instability in the recording the lower the Device Block Size is. I keep mine on 16 samples because my CPU is pretty powerful, but 32 or 64 samples may be better depending on your PC.

You can also look up Native Low Latency Monitoring on pages 14 and 15 in the Studio One reference manual. I think you also need to have Universal Control installed with the proper drivers for your DAC device.