I have this question from Co-Worker but I don't understand the meaning of the word "things", then don't know how to answer him.
If "things" is mean about the demo(example about work), I want to answer that " The things are well" but i'm not sure about grammar, please advise.
If he means "How are things going with [preparation for] the demo?", then you could answer "[Everything's] Going fine" or "Going slowly" or "Going badly" - depending on how things are going. You needn't use "things".