First registration

I Have landed in Brussels on July 8th and need to register within 8 days due to covid the registration is done online in the form they are asking for aNational Registration number, strange since I am a non EU citizen I do not have this 11 number, I can not complete the form without it, this their another  way to provide a different number I tried my passport number but did not work, an experience in this

Hi, I think you should first contact the immigration department of the municipality.

Hello
me to arrived with my family by D visa on July 11th. I don't know how to register?
What should we do after arrival. I'm quite lost. How to register in the city hall or who should I'm communicate?

They should have a `fake` number for this situation. Please, try contacting the provider of the online form.