change your preferred servers that appear in the main popup in the settings page - add / remove a server by using the + and x buttons and click "save & close settings" to save your preferences
when the 'private group' button is selected (white w. green border), the server buttons will send you into a private group on that server
when the 'joiner' button is selected, the server buttons will send you into the joiner for that server
谷歌浏览器、其他Chromium内核的浏览器