Please look in the FAQ section http://wordpress.org/extend/plugins/podpress/faq/ for the answer to the question "How can I add podcast episodes with podPress?". It contains links to forum threads where the basic procedure has been explained before.
Can I not because it's not a blog?
podPress is a plugin for WordPress. If the web site is based on WordPress then it should be possible to install podPress and to make a podcast. But the main principle of podPress is that one adds one (or maybe more) media file to a (blog) post. The result of that is one more RSS (or ATOM) feeds with post with (at least) one media file.
It is technically possible to attach multiple media files to one page. But I can not recommend that because it would very likely lead to performance problems of the page the more podcast episodes one would add. More importantly the episodes would not appear in the feeds.
podPress is only for attaching media files to posts and has no possibility to upload media files.
podPress adds the podcasts to the posts in the default feeds but it offers also the possibility to add additional feeds to your blog which will contain only posts with podcast episodes.
You can customise all these feeds on the Feed/iTunes Settings page of podPress. See this page http://www.apple.com/itunes/podcasts/specs.html#commontags to get an overview which settings influence what in the iTunes client software.
You may also use category feeds for your podcasts you can customise those feeds via Posts > Categories > Edit Category.