The law defines an apartment right as a share in the property included in the division, which includes the right to exclusive use of certain parts of the building intended to be used as a separate unit (article 5:106(4) BW). The share can also include exclusive use of parts of the land, such as a garden.
Legally, then, you are a co-owner of the whole building, with exclusive use of your own apartment. That explains why the VvE has a say in things you may feel are "yours", such as the façade or the roof.
With the exclusive right of use, you may use your private section yourself or let someone else use it, together with shared use of the common parts (article 5:120(1) BW). Exactly which parts fall under your right of use follows from the deed of division and the accompanying drawing.
See also: Apartment right (appartementsrecht), Private section (privé-gedeelte), Common parts (gemeenschappelijke gedeelten), Deed of division (splitsingsakte)
Read more: What is a VvE?
Legal basis: Boek 5 BW, art. 5:106, 5:120