Questions about Meldezettel

I’m a Brazilian redditor looking for some help and I would appreciate any advice from you. My german is very very basic, therefore I apologize for writing this in English. I’m moving soon to Vienna to work on a science research project.

My wife and I are going to stay in Vienna for 178 days (6 months) from September/2022 to February/2023. I’m looking for a place to rent and I’ve found some options. My only concern right now is about the registration in Austria. Once we move in, we have 3 days to fill out and register a Meldezettel.

I’m really confused about this form, as it is completely new to me. None of the places that I would rent for 6 months or less can be registered as main residence (at least that is what is advertised). The advertisers say ‘’ A secondary residence registration is possible.’’

In my case, can I just rent a place and register as a secondary residence for us? Will we be just fine doing that?

I can’t find any further information if a main residence is mandatory for a secondary residence. I searched about filling out a Meldezettel and found some examples on Youtube or Internet. I always see people checking the box in the form as main residence (example: [https://www.youtube.com/watch?v=74rHD95mXLA&t=1105s](https://www.youtube.com/watch?v=74rHD95mXLA&t=1105s)). Checking the box JA for Ist diese Unterkunft Hauptwohnsitz?

Hauptwohnsitz is the same as main residence? Or is it just my principal address and it does not matter if it is a main or secondary residence?

I’ve tried to ask this in r/Wien but did get only one answer that my main residence would be my current Brazilian address and I would register just fine with a secondary residence for the period (less than 6 months) that I will be in Austria. I’m not sure if this is true…

If anyone has experience with Meldezettel and can answer this, I would appreciate it.

I’m completely lost and I don’t feel confident in renting a place because of this document.

I have directly asked about this for a landlord that owns a studio that I’m interested in. She said that I will receive a registration form from her, after asking about the Meldezettel and she also said that my main address would still be my Brazilian address.

Thank you so much for your attention Reddit.