Ruby has classes but they are all implemented as objects. Some objects act as classes but some of them do not. For example "string" and String are both objects -- "string" being a String class object, and String being the class. Since classes are also objects, String is still an object while "string" is not a class -- ONLY an object.
To create an instance of a class, use that class's "new" method. For example, if we had a class called "Cat" we would instantiate it using the following syntax:
Cat.new