How to set TradeMesseger's alert sound and alert information?

Enter TradeMesseger's Homepage, click "Settings" in "System Menu", select "Alerts" in "Chat Settings" in pop-up window, and then choose the way you would like to receive an alert.

How to add custom user photo in TradeMesseger?

How to set "No Messages from Strangers" in TradeMessenger?

How to turn off message alert sound in TradeMessenger?

What's the difference between private group and public one?