I am planning to apply for a Schengen Visa in the near future through the Spanish Embassy in London. I am a Turkish citizen who studies in the UK, hence a UK resident (but not a citizen). I was just wondering, when I am applying for a Multi-Visit visa, do I need to prove every single travel that I intend to do with flight reservations, hotel bookings etc. I will be staying in Spain for 4 days and I have all relevant documents for that, however, I plan on visiting Amsterdam and/or Paris in the future with my flatmates, the dates of which are unplanned as of now.
For reference, my mother who lives and works in Turkey, recently got a Multi-Entry Schengen Visa for 1 year even though she only had to prove her 3 days travel to Greece.