If you have an Oracle server running remotely on a network, and you know all the access information needed, you can following steps to connect your Oracle SQL Developer:

► Start Oracle SQL Developer

► Right-click on Connections

► Select New Database Connection

► Enter Connection Name as: Remote_Server

► Enter Username as: _username_

► Enter Password as: _password_

► Enter Hostname as: _hostname_

► Enter SID as: _sidname_

► Click Test

► Click Connect, if you see Status changed to Success

You will see the SQL Statement area opened ready to take any SQL statements.