It can indeed be complex. It depends on what type of law it is, in this case it’s a regulation so there is no need for countries to ratify it:
Regulations
Regulations are legal acts that apply automatically and uniformly to all EU countries as soon as they enter into force, without needing to be transposed into national law. They are binding in their entirety on all EU countries.
It can indeed be complex. It depends on what type of law it is, in this case it’s a regulation so there is no need for countries to ratify it:
https://commission.europa.eu/law/law-making-process/types-eu-law_en