I opened an account myself on the advice of a friend who told me to go to the bank and say that I am ready to get life insurance through them and then all I had to do was haggle over the cost of the insurance and after a year I did not renew the insurance. They just profit from the insurance. Money solves every problem in Thailand.
The necessary documents: photocopy of passport including photocopy of the entry stamp. Proof of residence and address, photocopy of the bank account book including confirmation from the bank that you have 800,000 baht for the last three months, filling out the T7 form.
I just wanted to make it clear, I have no complaints about agents and the service they give to customers. Not everyone is built and able to organize all the paperwork properly. What amazed me was how fast it went today, in the past I spent hours waiting for every little matter.