It looks like you’re asking for a guide on in relation to DP ADVF (likely the Diploma Programme (DP) Advanced level of the Analysis and Approaches or Applications and Interpretation courses from the IB, or possibly an advanced forensic/critical thinking module).
Since “Doyle” strongly suggests (creator of Sherlock Holmes), I’ll assume you need a guide to conducting a literary or forensic-style investigation using Doyle’s narrative techniques, adapted for an advanced DP-level assignment (e.g., an Individual Oral, HL essay, or a past paper on detective fiction). doyle's investigationdp advf