Each dictionary has attributes, based on these attributes you can match authentication or authorization rules,
So which Dictionary and Attribute do we need to choose? That's depend on your deployment if it is (Wired/Wireless 802.1x with/without AD, and which EAP method used ? and so on ...) need more info.
I invite you to take a look on this valuable document ISE Network Access Attributes for the explanation of each of the default attributes on ISE.
Also, i recommend you to check labminutes.com for Cisco ISE Video's.
Hope that helps!