Automatic time date stamp at beginning of each line

Thank you. My first file is normal. i just want my A row has the same formula. Like if i but something in b3 so a3 inserst date automatiacally. Just like your file. But i dont know the general formula for it? Can you please be more specific and more noob friendly? Thanks

I put this IF(B12="","",IF(A12="",NOW(),A12)) into cell A12 and click ok and exit. Then when i type anything on b12. it shows err:522 in a12

Thank you, I trying checking that box.
Not when i tyep something in cell B12 , it gives a weird number like 432435.3434 something like that in A12

If you want to get shown a numeric value as date-time you need to format the cell concerned appropriately. Read about number formats first. Use the format code (English locales) “YYYY-MM-DD HH:MM:SS” whereever possible for date-time.
If you got shown the value you posted above you urgently need to get back to our time first. Presently you are living on 3083-12-18. The edit you made was 08:14:29.7600. Go back about 1067 years, please.

Thanks for trying to help. But i really dont understand. Can u please make a empty file for me with A1 row done? please? Thanks

Nevermind, I just coppied the cell from your file to mine and it worked. Hope it dont get messed up liek you mentioned,
Thank you. I didnt know calc needs programming skills

@CCGirl: Using calc for more than just typing something into a few cells surely requires a mnimum of “initialistion” on the side of the user. Reading a guide might help. Help texts sometimes, too. Some concious steps of trial-and-error are useful. Working with a rather sophisticated proposition by someone who explicitly advises to only rely on it if understood, is not the best way to start. Yes. It may get messed up. Should i write a treatise about the circumstances now?