SQL Server, odbc newbie question
If you're using SQL Server Management Studio (SSMS), you don't need to "create" a connection via ODBC, you can just connect directly to the server via the SSMS user interface:  



In SQL Server, the equivalent of an Oracle "database server" is called a "SQL Server Instance".  It can contain many databases, which are similar to a "schema" in Oracle.

So, when you connect via SSMS, you connect to the instance, which takes the form of:

COMPUTERNAME


For a "default, unnamed" instance, or for a "named" instance:

COMPUTERNAME\INSTANCENAME


INSTANCENAME gets resolved to a port automatically by the SQL Server Browser Service; if that service is not running, or is blocked by a firewall, you may need to connect using the port number, as in:

tcp://COMPUTERNAME,0000


where 0000 is the port number for the instance.

If you don't have access to the instance, you'll see an "authentication failed" error message.  If SSMS cannot contact the instance because of a firewall, or the server is not listening on the port you specified, you'll see an error indicating that, similar to:


  "A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible.   Verify that the instance name is correct and that SQL Server is configured to allow remote connections. "


To create a connection via ODBC, you open the ODBC Data Source Administrator from the Windows Control Panel.  You can either create a "User DSN" or a "System DSN", either way choose the SQL Server Native Client 12.0 driver:



Fill in the details (use the servername as detailed above):



Accept the defaults for the rest of the configuration screens if you plan to use integrated Active Directory domain authentication.  If the login will be made using a SQL Server Login, enter those details on this screen: