I am here without my parents
If you are under 18 and you are here without someone who has parental authority or guardianship over you, you are an unaccompanied minor. Even if you are here together with, for example, your uncle or grandmother who does not have guardianship over you (recognised by Belgium), you are an unaccompanied minor.
You will be given a guardian who will legally represent you and look after your safety and well-being. You cannot live with your guardian. There is a waiting list, so you may have to wait a while for a guardian.
More information on what your guardian does can be found here (brochure in Ukrainian).