http://www.ind.nl/EN/verblijfwijzer/
You will need:
* a valid passport
* proof of your travel objective (for instance an invitation letter)
* proof that you have sufficient funds for your stay, transit journey and/or return journey
* where applicable a guarantor’s declaration <-------
* proof of a medical travel insurance with a minimum coverage of € 30.000,-
* a reservation for the journey
* documents showing that you intend to return to your country of origin (for instance an employer’s declaration,
* proof of registration of school-age children or proof that you own your own home)
* two passport photographs
* If you want to come to the Netherlands for a medical treatment: declaration of a doctor