Why do you want to use COM instead of the driver PHP provides for connecting to SQL Server ([man]pdo-sqlsrv[/man])?
As for how it's used, it's like the other interfaces to SQL databases:
Write SQL query.
Send to server
Get results
???
Profit!
Are you asking about resources for learning SQL? The specific dialect of SQL used by SQL Server is covered in its documentation?
("Connect without a DSN (using a connection string)" - of course, the connection string is a DSN....)