Click on the menu "hamburger" button on the top left side Select Options You can now choose from various sounds, themes and font size. Green means enabled, Red means disabled.
Sound alerts are: New Messages (can be loud, as a tone will be heard with each new message posted in a room) New Personal Messages (recommend to leave on so you'll know when someone is writing just you) Join/Left Messages (can be loud in a busy room, will make a tone when anyone enters/leaves a room you are in) System Messages (recommend you leave on to receive notice of important system messages).