Go to SE24 and provide some class example ex: CL_ABAP_CHAR_UTILITIES, to see what are the components of class.
Properties: The properties tab contains class properties like created user name, last changed user name, package etc.
Interfaces: Contains the list of the interfaces that are implemented in this class( will discuss in later lessons).
Friends: contains friend classes ( we will discuss later lessons).
Attributes: The attributes tab contains the list of attributes declared in that class.
Methods : Contains the methods with importing and exporting parameters and with some business functionality (source code).
Events: Contains events declared and implemented in that class.
Types: The types tab contains user defined type decelerations.
Aliases: Contains alias names for interface methods ( will discuss in later lessons).