How to buy the roof of my building?


I live in an apartment building (In Israel) on the top floor.

I and the other apartment on my floor want to buy the roof all so we can expand our apartments.

In order to do that we need to:
1) get the consent of 75% of all the apartment owners.
2) Pay them/renovate the building.

I FEEL very stressed about it, almost convinced there is no way I can make it happen (obviously not the best way to do something…).
This feeling is based on knowing the neighbors and especially 3 apartment owners (out of 12) that will probably be against it. (Though they are not on the top floor, and can’t really use the roof),

My questions – How should I go on this process.?
What should I do?
What questions should I ask…
Any guidance….

I joined scholars to help me get this done…

Thank you!