Short answer:

• In the Digambar tradition, during Das Lakshan (Dashalakshana vrata) devotees observe ten separate fasts, one for each of the ten lakshanas (auspicious signs) of a Tirthankara’s life. Each day’s fast is a step toward greater restraint, and the rules for how strictly one fasts can vary by teacher or temple.

What this typically involves (high level):

• Ten days of fasting, with the emphasis on self-control of food, speech, and thoughts.
• The progression is from lighter to stricter fasting across the ten days, aligning with the respective lakshana being reflected upon.
• On many days, people begin with a regular meal and gradually reduce intake; on some days the fast may be very strict (very little or no food), depending on local practice and guidance from one’s guru or acharya.
• The aim is purification and mindfulness, keeping the focus on ahimsa (non-harm) and self-discipline.

Differences you may notice:

• Digambar and Shwetambar communities may have different detailed rules for each day’s fast, and the exact observance can differ by region, temple, or guru.
• In some places, lay followers perform light fasts (e.g., one meal a day) on certain days, while monks/nuns follow stricter rules.

If you’d like, I can look up a specific Digambar practice for a particular temple or teacher and provide the exact day-by-day fasting rules.