That's understandable, but it's one very simple form, information provided by your bank, some photocopies and passport photo. So 90% of people will have no problem navigating the process, if they try.
It seems bewildering when you are at the planning stage, but when you start the process you realise it is quite simple really.
Get a non O visa based on retirement before you come to Thailand online from the Thai Embassy.
Travel to Thailand, open a bank account and transfer 800,000 baht immediately.
Go to immigration and get a list of their requirements to extend your stay.
Wait until your money has been in your account for 2 months then go to the immigration office with everything on their list of requirements. You will need to complete one A4 form with simple questions like; name, passport number, date of arrival etc. Pay 1,900 Baht and that's it for a year.
You do the immigration office part each year to extendyour stay for another year. Good luck.
As others have stated it is not necessary, but if you want to change to the monthly income method in a year, you need to deposit 65,000 Baht per month for 12 months to qualify next year.