Open Oracle SQLDeveloper
Right click on connection tab and select new connection
Enter HR_ORCL in connection name and HR for the username and password.
Specify localhost for your Hostname and enter ORCL for the SID.
Click Test.
The status of the connection Test Successfully.
The connection was not saved however click on Save button to save the connection. And then click on Connect button to connect your database.
The connection is saved and you see the connection list.