U hv to first decide in which Country you are going to spend the maximum number of days and if you planning on spending equal number of days in all places then visa has to be obtained from that Country which is going to be your point of entry...the rest of the itinerary can be planned after you get the visa...What we do is we book our Round trip flight ticket which is a refundable one to avoid losing money incase there is a visa issue.... next we book hotels on bookings.com and select those hotels which have a free cancellation option so that incase visa is denied or we change our Itinerary, we can cancel without being charged. They do not ask for proof of Internal flight or train bookings... so u just have to mention how u plan to travel from one place to the other in the Itinerary u will present for Visa purpose.
While applying you have to give them an approximate itinerary. There's always a possibility to change it later on. We applied with a different one and on the travel days we had to changed it. We were supposed to get back from vienna but instead we came out of prague. Once you get the visa it is completely ok to change it later on provided you stay in the schengen area. Also Swiss Embassy is one of the easiest to get the Schengen visa. Depending upon your travel history they will give you visa with more validity. ( Thought we applied for 15 days we got visas for 6 months due to our extensive traveling )
You can directly apply through the country which is your port of entry. Either you can apply through VFS which is a 3rd party or directly thru embassy of your port of entry country.
You need the following:-
1)Passport size photo
4)Filled application form
7)its good to have local sightseeing tours booking (though not mandatory)
9)Leave/NOC from your work place.