After you have a TIN, you can file online by yourself.
The Revenue Department has an end-user friendly online site to file.
A Chrome Browser is able to translate the entire process into English.
Determine, to the best of your ability, your assessable income for 2024.
If necessary, find help to do this in the private sector (not the Revenue Department).
You don't need to pay anyone to file once you're determined your assessable income.
Enter your information into the Revenue Department's online site and file. Pay by QR code if you owe taxes.
Finished. You're a tax resident here (>180 days) and have successfully filed.
If the Revenue Department has questions, they will ask.
Keep good notes and records for this possibility - just like your home country taxes.
I would not expect, or want, the Revenue Department front line staff to advise about evaluating my finances for assessable income.
Or assistance with filing....
I think most would not have that expectation of their home country Revenue Department equivalents.
Search for Revenue Department's online e-file site (efiling.rd.go.th). Right click on Google Chrome and select translate to English
For those without a TIN, you can go to the Revenue Department and apply for a TIN.
Just that one task. Nothing else....
You’re not there for their assistance to file your taxes.
You already have someone to do that.