@Avtar ********
I'm not sure you can the 40kthb method in the first year, you cant on some other visas. If someone knows on here thats fine if immigration can help. In addition to financial proof, other document proofs include:
The passport of the applicant with all relevant visas, stamps, and TM6 departure card,
The child's Thai ID card and house registration (housebook),
Evidence of parental rights such as a court order or marriage certificate,
Photographs of the applicant and child,
The submitted TM7 extension of stay form and TM30 residence notification.
But again immigration can confirm