how will people outside the country vote?

The referendum day is coming closer and closer and i havent heard any news about how the people outside the country can vote . there are a lot of citizens in other countries and they should be able to vote. there are embassies in most countries.they said that police and the army can vote so should the people outside the country also should be able to vote there should be a way they can participate afterall they are citizens of this country and this referendum is going to decide our future. the future should be decided with their say in it. hope the elections do consider a way to let them vote and make it public so everybody knows how they can vote