- BNL 1 means that the visa was issued following authorisation by the central authorities.
- BNL 5 + 3 DGN (3 days) means that the visa holder must report to the police within 3 days.
A D+C visa allows you to enter the Schengen area at any border of a Schengen state (such as Germany) , transit through the German territory, enter the Netherlands and report to the Dutch police within 3 days after your arrival in the Netherlands et apply for a residence permit, I suppose.
During the first three months after your arrival, you are allowed to travel within the Schengen area. During that time, you should receive your residence permit.