In the Shwetambar tradition, there isn’t a single fixed “doha” from the Agams specifically for beginning Kesar Pooja. The pure and universal way to start is:

1) Navkar (Namokar) Mantra

• णमो अरिहंताणं।
• णमो सिद्धाणं।
• णमो आयरियाणं।
• णमो उवज्झायाणं।
• णमो लोए सव्वसाहूणं।
• एसो णवकारो, सव्वपावप्पणासणो।
• मंगलाणं च सव्वेसिं, पडमं हवई मंगलं।

Arth (simple meaning): I bow to Arihant, Siddha, Āchārya, Upādhyāy, and all Sādhus-Sādhvīs. This five-fold salutation destroys all sins and is the foremost among auspicious things.

2) Mangalam Shloka (commonly recited as mangalācharaṇ before pooja)

• मंगलं भगवान वीरः, मंगलं गौतमो गुरुः।
• मंगलं कुन्दकुन्दाद्यो, जैनधर्मोस्तु मंगलं॥

Arth: Auspicious is Bhagwān Vīra (Mahavir), auspicious is Guru Gautam; auspicious are the great Āchāryas like Kundakund; auspicious is Jain Dharma.

After this, begin Kesar Pooja with shuddha bhāv, following the Ashta-prakāri or your local paddhati.

For a simple guide on Navkar Mantra and Puja meaning, you can refer here:

• Navkar Mantra overview
• Meaning of Ashta Prakari Puja