A good starting point is Tone 3–4 (it is a bright pedal), Level 5, Distortion 5. Roll the Tone back to warm it up and keep the Distortion moderate for a musical crunch.
Why does my DS-1 sound harsh?
The DS-1 is a naturally bright, mid-scooped distortion. Lower the Tone control toward 3–4, back the Distortion off to around 5, and run it into an amp with some midrange to counter the harshness.
Recommended starting points are community-researched estimates — every pedal, amp and guitar is different. Dial from here, then GuitarToneAdapt helps you match a target tone on your own rig. Pedal comparisons · Amp settings · All tones