The binding legal principles established are: (1) Grounds of appeal must be clear, concise, and specific, informing the trial court, respondent, and appellate court of the particular findings being challenged. Vague and general grounds that amount to merely saying "I am not guilty because I am not guilty" are invalid. (2) A trial court has no duty to call witnesses to present evidence, particularly where an unrepresented accused is able to appreciate the materiality of such evidence to their own defence. If an accused considers evidence relevant to their defence, they must call that witness themselves. (3) Where a trial magistrate has properly explained procedural rights (such as those under ss 188 and 189 of the Criminal Procedure and Evidence Act) to an unrepresented accused and the accused demonstrates understanding, the magistrate has fulfilled their duty. Any subsequent failure by the accused to conduct effective cross-examination or properly present their defence cannot be attributed to the magistrate's failure. (4) It is competent for a court to draw inferences from undisputed and unchallenged evidence to establish guilt beyond reasonable doubt, particularly where fundamental features of the prosecution's case are common cause.