Robert Lagas as Matthew answered already, just save it and you're done. You can always retrieve it to check it's stored in the system. For evidence, if needed, do a screen print.
calculated correctly 17.Feb.2019. As Chiang Mai ist hard core about TM30 ( reporting address within 24 hours after arrival ) make sure that your landlord has done this and get a confirmation.
Daniel Wolfe don't brood,get the O-A as James Miller stated , follow the rules and enjoy up to 2 years stress-free living in Thailand. Then decide yearly extensions or start again O-A.