Help installing "Post Indexer" plugin.

I know this is probably a stupid question I just want to be sure.

Download post-indexer.php and place it in /wp-content/mu-plugins

1) Place the files in the specified directories

This means just add the post-indexer.php into mu-plugins correct?

2) If the auto-install does not add the db table(s) for you then run the sql code in "sql.txt" on your wpmu db

How do I know if the db tables were created?
If they were not, how do I run the SQL code in my wpmu db and what exactly is my WPMU db? Would that be the MySQL database I created to install WPMU?

Thanks all.