A quick Google search for “iata ahm pdf free download” will return results from domains like pdfdrive.com , freepdf-books.org , or aviationlibrary.org . Most of these sites operate in legal grey zones.
While this seems expensive, compare it to the cost of a single ground incident (e.g., a towbar breaking a jet bridge costs ~$50k to repair). The manual is insurance. iata ahm pdf free download