Need hep with this task!

Create an address book application using JavaScript (plus HTML and CSS). (Use plain JavaScript, no third party libraries!)

The required functionality is the following:

• Entries
  • Entries have the following fields: name, telephone number, email
  • Individual entries must be represented as an Entry object
  • The contact list must be represented as an array of Entry objects
  • The application must be shipped with some sample initial data (meaning, with a non-empty address book)
• Display a list of entries
  • Emails should be clickable links that open in the mail client
• Add a search field to filter the list
  • Only those entries are displayed that contain the searched string as part of the name, telephone, or email
  • Matching is case-insensitive
• The user can delete existing entries
  • Ask for a confirmation before deleting the entry
• The user can add new entries
  • Perform input check
    • The name field must never be empty
    • Either tel or email has to be filled in
    • Email has to be a valid email
    • Tel may contain only numbers and + - ( ) and space