The first step in forensic analysis is to collect the most volatile data, which is the information that would be lost when the power is turned off or the system is rebooted. This includes the contents of memory (RAM) and other temporary data that are stored in caches or buffers. A memory dump captures this data and should be done before other less volatile data is collected, like hard drive images or log files, to ensure the most accurate and comprehensive capture of the system's state at the time of the incident.