During Paryushan Parva, Jains focus on heightened spiritual practices, including Chaityavandan, which is a ritual of worship and prayer in front of the Jina idols or at home.

On Day 1 of Paryushan Parva, there is no single, universally mandated Chaityavandan for all Jains as practices may vary slightly among sects (Shwetambar and Digambar) and traditions. However, it is common and appropriate to perform the regular Chaityavandan with special emphasis on Samayik (equanimity), Pratikraman (repentance), and Kshamapana (asking for forgiveness).

For Shwetambar Jains, you may recite:

• The standard Dev Vandana (Namaskar Mahamantra, Panchindiya Sutra, Iriyavahiya Sutra, etc.)
• Perform Samayik and Pratikraman
• Include the recitation of Kshamapana Sutra or Michchhami Dukkadam

For Digambar Jains, you may recite:

• The regular Dev Vandana (Namokar Mantra, Chaityavandan Sutras)
• Special Pratikraman and Kshamapana

Summary: On Day 1 of Paryushan Parva, you should perform your regular Chaityavandan with special devotion, focusing on humility, repentance, and forgiveness. You can also consult your local Jain Sangh or Guru for any specific recitations or additions recommended by your tradition.