How can I extend my 60-day Thai visa and what documents are needed for the process?

Although I have been coming to Thailand since 2003, this trip is the first time I have ever applied for a visa. I got myself a 60 day from London before I came out. Once the UK put Thailand on their red list I started thinking about staying longer to avoid 19 days in a cheap hotel with a high price tag upon my return. Not wanting to get anything wrong I went over to Kalasin immigration at 16.00 today, just to ask what I needed to get an extension. I left at 16.30 with a thirty day extension in my passport to start on the 30th of this month. The people in there could not have been more helpful and worked right up to clocking off time so I didn’t have to go back. I have read many horror stories before so went in ready for a long slog. Still smiling that I have my stamp and can now stay to the end of October.thank you Kalasin Immigration, a good team you have there.