The ratio decidendi of a case consists of the material facts of that case, together with the rule or rules of law that the court decided should be applied to those facts to decide the case. The ratio decidendi forms the precedent set by that case.
All the other comments made by the court while deciding the case do not form part of the ratio decidendi and are described as 'obiter dicta', which roughly means 'surrounding words' or 'additional comments'.