Bueno theme customization

I am very new to WordPress and am trying to customize the Bueno theme. Three questions:

1) In the WordPress.com version of Bueno, the site’s tagline is in the top black bar. In the .org version, it’s a category. In this case, it says “Uncategorized”. How do I remove the category and make it the tagline?

2) I have turned off comments from the site, but posts still list the number of comments under them. How do I remove that?

3) Where do I find the style sheet that I need to tinker with in order to change the color scheme?

Thank you!