Question for Sayed Mohamed Hussein Fadlallah Public Library

I follow sayed mohamad hussain fadhlallah for almost 16 years, is there a specific marja i need to follow in regards of questions about khums or zakaat or eid, is there somone present that takes after him, because he died, is it compulsory to follow somone that is present to give us instructions about eid ect and to answer our questions