The correct document to guide hardware changes and ensure they are properly documented is the Standard Operating Procedures (SOPs) document. SOPs provide a detailed framework for performing tasks and keeping consistent records within the organization. Log reviews are a way to inspect already recorded logs, but they do not provide a process for documentation. Availability reports focus on the readiness and performance of systems rather than documenting procedures. Vendor documentation supplies information about the hardware itself but not about the company's specific documentation process for hardware changes.