When applying for a Schengen Visa in order to travel to one or more of the Schengen Zone countries there are some requirements one has to establish prior to the application. If you are planning to travel to more than one Schengen country its best if you apply in the Embassy/ Consulate of the country you will be staying at the most, regarding the residing days. Once you are issued a multiple entry visa you are able to travel to all of the Schengen Zone countries for the time permitted on the visa.
When applying for the visa you should bear in mind that you have to personally hand the required documents once you have made an appointment at the embassy/consulate. It is always recommendable to arrange the appointment at least 15 days prior to your departure since that is the estimated time needed for the bureaucratic process taking part in the corresponding institution.