@Christine ****
You are confusing TWO separate things but FIRST lemme give you some sage advice;
NEVER EVER trust a worker at a thai consulate OUTSIDE the country about any immigration related stuff inside the country.
AND
NEVER EVER trust a worker at the immigration office INSIDE the country about any visa related stuff outside the country.
They are two completely different governmental agencies that rarely talk to each other.
As people correctly told you; you are obligated to file a TM30 within 24 hours of arriving at your residence, and seeing as you're in Chiang Mai you can do it 7 days a week at the immigration office by the airport.
Now after that once you're in country 90 days you need to file a 90 day report. Which has NOTHING to do with filing a TM30 within 24 hours..