By pedrxd
1) Download the plugin ( https://github.com/pedrxd/TeamChanger-b3/archive/master.zip ) and unzip it.
2) Copy the content of extplugins to the b3 extplugins folder.
3) Add on b3.xml the following line
< plugin name="teamchanger" />
!red [] //Dont need explanation. !blue [] !spec [] !auto [] //The same as do auto on game. !replay [] //Go spec then join a team.