Discover processes , Scanning , Classification , Identification, Exploration
Classification
If Discovery finds devices or computers, it sends additional probes to find the type of device or the operating system on the device. For example, Discovery sends the WMI probe to a Windows machine to detect the Windows 2012 operating system. Then Discovery uses records called classifiers, which specify the trigger probe or probes that run during the next two phases. If you are using patterns, the classifier specifies a trigger probe that in turn launches a pattern.
Here credentials are used

The identifier launches additional probes configured in the classifier. These probes are especially designed as exploration probes to gather additional information about the device, like the applications running it, and additional attributes, such as memory, network cards, and drivers. Discovery then creates relationships between applications and devices and between applications. If you are using patterns, the operations in the pattern perform the exploration of the CI.