The higher the [[quality]], the more you can write on the sign, at a ratio of 1 letter per each whole quality. To write on the sign it must be in your [[inventory]]. Right click and select Rename and enter your message.
To plant the sign simply stand in place, right click on the sign in your inventory and select Plant. Once planted the sign may be pushed, pulled or rotated by using the right-click interface. Only the player who planed planted the sign may move or remove the sign.