I am interested in using the blog module, but have had trouble finding basic documentation. On the blog module page I see a couple of links ( Installation steps and Getting started), but they're essentially broken (the content that should be there is gone.) I've looked for their content elsewhere, but haven't been able to find it.

In any case, what I'm interesting in finding out is how to set the language used for the blog's interface, and how to specify the blog themes (assuming the blog module still uses themes).

In any case, what I'm interesting in finding out is how to set the language used for the blog's interface, and how to specify the blog themes (assuming the blog module still uses themes).

Both of these simply use the built in mechanisms. For language see http://doc.silverstripe.org/sapphire/en/topics/i18n and for themes - it uses the current theme you set, but it will also load a yourthemename_blog subtheme (http://doc.silverstripe.org/sapphire/en/topics/theme-development)

Regarding the broken links - docs.silverstripe.org now only has the official documentation. If you want to read information regarding the module check for a 'docs' folder inside the module. This will contain a series of text files which has the documentation for your release. For blog you can see it in the source at https://github.com/silverstripe/silverstripe-blog/tree/master/docs/

Thank you for your help, Willr.