Can someone clearly explain when to use which one?
@ - used for simple commands (the next command will not happen until this command has finished)
@DUDE is laugh_giggle @CHICK is eyeroll
DUDE will laugh first, then chick will eyeroll once DUDE has completed his animation
& - used in place of @ when you want a command to happen simultaneously while other commands are happening (this command will happen at the same time as other commands)
&DUDE is laugh_giggle @CHICK is eyeroll
DUDE will laugh while CHICK is doing the animation eyeroll
AND/and - used to combine more than one command on a line (two or more commands will happen at the same time)
@DUDE is laugh_giggle AND CHICK is eyeroll
Both DUDE and CHICK will do their animations at the same time.
Have a look here as well, all explained with examples