Create Hashmaps Where Inner Hashmap Contains Key As Firstname

my query is like: "i want to create hashmaps where the inner hashmap contains the key as firstname and value as a Class Student which contains parameters firstname, lastname,etc. I need this hashmap to be accessed by other objects of different classes".

public class Student {
private String FirstName;
private String LastName;
private String EmailAddress;
private String PhoneNumber;
private String Username;
private String Password;
private String EducationalInstitution;

[code]....

As we give the values by Scanner, it should be Stored in Hashmap and how those values can be accessed by other object classes?How does the Logic works? What my next step?