Boy, they sure don't make learning this SQL server stuff easy with these downloads! Finally got the pubs attached, but got errors when I tried to do the walkthrough program.

So from within the SQL server mgt. studio express, I tried clicking on the database diagram and got an error message regarding authentication. (I had attached the pubs database to my SQL server.) AFter doing some research, found the following article.

Under this article it warns that you may get an error if you attached your database:
<start quote>
The installation of these support objects can fail on a database that has been attached or restored from another instance of SQL Server. This may occur when the database owner name (stored in the database) is not a valid login in the instance of SQL Server the database is being attached or restored to.
Use the following Transact-SQL expression to change the database owner to a valid login in the instance of SQL Server. Then retry the database diagram operation.

ALTER AUTHORIZATION ON DATABASE::database_name TO valid_login

<end of quote>
Where do I go to do this? Which program do I open and which part of it do I open to change this authorization on database. Also, I don't know what my valid login is either. (I'm the only one using my computer.)

Can someone clue me in how to do this?