Actual payment process (cash / cashiers cheque) changes land office by land office. Also note that if the cashiers cheque was written at a bank in a different region of Thailand there could be a 2, 3, 4, 5 days delay in clearing the cheque (even if it's a bank cashiers cheque). This should be discussed and agreed in detail in advance with the buyer.
I'm aware of a house sale in Pattaya, buyer presented a bank cashiers cheque at the land office. Seller said "I'm not handing over the keys until my bank clears this cheque". It took 5 days to clear. Buyer went back to land office and complained. Land office senior said "until the seller gets the money (cheque is cleared) you have not paid, you have to wait".