Interpol has recently published the "Global Guidelines for Digital Forensics Laboratories" manual that is freely downloadable from the Interpol website following this link: https://www.interpol.int/content/download/13501/file/INTERPOL_DFL_GlobalGuidelinesDigitalForensicsLaboratory.pdf
The manual describes the guidelines and procedures for the establishment and management of a digital forensics laboratory; the characteristics and physical safety of the premises, the skills and duties of the staff, the recommended hardware and software equipment.
The manual also provides guidelines on how to conduct a digital forensic investigation, analyzing the various phases: acquisition, extraction, analysis and preparation of the final report.
The manual is completed with some appendices with checklists, facsimile of models for data acquisition and analysis and for reports and flow charts that illustrate the procedures to be followed in the various phases of the investigation.