Player::kill(%player,%damagetype); - %player is a player object, %damagetype = $DamageType::Gun etc
%player.kill(%damagetype); - %player is a player object, %damagetype = $DamageType::Gun etc
%player.schedule(%time,kill,%damagetype); - Note there is no '0' between the time and function 'kill', when scheduling with an object. %time is in milliseconds, 3000 = 3 seconds.
When running a server, put $DamageType:: into the console then press Tab to see all the possible damage types you can use.