Have you read your Owner Manual? You seem to have a lot of questions that are answered in it.
I found this with "air filter" in the search box http://www.chevyhhr.net/forums/%22ho...ght=air+filter
I'm pretty sure somebody has posted a how-to on the air filter, too. You might want to explore the site, you can't break anything by pushing buttons on your mouse.
Once again, I point to the link in my sig.
Online Owners Manual
After I posted this I made a How-To sticky in the how-to forum. How to replace engine air cleaner/filter