How to chat with seller/buyer, without opening the trade?
Not every information / detail is included in the description and terms of the transaction, or the information is not precise. Then I need to explain the information/data, without having to start a new transaction, that later hangs in the history like a cadaver in a closet. (like this word: cadaver 
black humor)
Hello!
You can open a trade, discuss the details, and if it doesn’t work out - simply cancel the trade. There’s no way to communicate without opening a trade.