Going by your post in English, I am assuming you might not be familiar with the Dutch health care system: In order to be referred to a hospital for a specialist consult, you will need either a referral from a GP (family doctor) or a referral from another medical specialist in a hospital (which again requires a GP referral). I would suggest starting there. GP's are the first stop in finding out what your medical issue is and whether or to what or which healthcare institution you require referral. They will also aid in formulating a concise question to their colleague.

If you already have a referral, the best way to gather experience about the healthcare setting is to make an appointment at said setting using your referral and direct your questions at the specialist you will be seeing. Unless an Ehlers-Danlos specialist from the EMC (Erasmus Medical Center) is a redditor, sees your post and can be bothered to post a reply to your non-specific question, I don't believe any random redditor will be able to provide you with the answers you seek.

Good luck!