To set up nnir you may need to do some prep work. Firstly, you
may need to configure the search engines you plan to use. Some of
them, like imap and gmane, need no
special configuration. Others, like namazu and
swish, require configuration as described below.
Secondly, you need to associate a search engine with a server or
a backend.
If you just want to use the imap engine to search
nnimap servers, and the gmane engine to
search gmane then you don't have to do anything. But
you might want to read the details of the query language
anyway.