The present document constitutes the deliverable D8.4 “Guidelines for the advisory system and its components” in the framework of the project entitled “Optimization and performance improving in metal industry by digital technologies” (Project Acronym: INEVITABLE; Grant agreement no.: 869815). It is based on the project proposal form established in the Grant Agreement and signed by the European Commission and the project coordinator. The main objective of this deliverable is to describe the guidelines for the advisory systems in the steel plant environment of the industrial partners Sidenor (SID) and voestalpine (VAS).