You will require a Dutch bank account into which your salary will be paid and from which expenses such as utilities, local taxes and your rent will be paid. For this you'll need the following documents:
Signed employment contracts
Signed rental agreement
South African TAX numbers
* If you do not yet have a BSN number you can make an appointment for a bank account through ABN Amro (via their banking app). Other options include mobile banking providers such as BUNQ or Revolut. You will have 90 days after opening your bank account, with either of these banking options, to provide your BSN number.