Translation core doesn't work

Hi there,

I’ve been working on the translation for days. I want to translate multiple sentences such as indicate mandatory field, description, preview, publish.. into Thai. I read the instruction on translation core and tried following them. I load the program “poedit” and got the .po and .mo. I think I might have missed something because I tried putting both files to the specific folder as said in the couple suggestion still not thing change. Could you please help me?

Thanks,
Fon