Answer

If you mean the 108 Parshvanath tap, the exact vidhi can vary by gacch, sangh, and local tradition. In general, the practice is done with bhakti, discipline, and purity of conduct under guidance from a Jain guru or temple tradition.

Explanation

Commonly, one should do the following:

• Keep the body and mind clean before starting.
• Take a clear sankalp for the tap.
• Follow the prescribed fasting or austerity as told in your tradition.
• Do Parshvanath bhakti daily:

- darshan - puja, if allowed in your tradition - stavan or stotra of Shri Parshvanath - jap of the Parshvanath mantra or related prayer, if given by your guru

• Observe Jain discipline:

- ahimsa - truth - brahmacharya - non-attachment - control over food and speech

• Do pratikraman / repentance regularly.
• Avoid anger, gossip, harsh speech, and worldly indulgence during the tap period.
• Serve others with humility and maintain simple living.

Spiritual Understanding

The purpose of Parshvanath tap is not only outer austerity, but also:

• purification of karma
• strengthening of faith
• deep devotion to Shri Parshvanath Bhagwan
• growth in self-control and inner peace

In Jain Dharma, tapas becomes powerful when it is joined with right faith, right conduct, and purity of intention.

Takeaway

The safest and most traditional advice is: follow the exact vidhi given by your guru or local Jain sangh, and keep the tap focused on bhakti, discipline, and non-attachment.

If you want, I can also give you a simple daily routine for 108 Parshvanath tap in easy steps.