Searching gmane messages from Gnus

[Garjola Dindi]

Hi,

How can I search messages from a news group like nntp+news.gmane.io ?

The Gnus manual gives information about search engines which need to
create local index files, but is this the way to search nntp servers? I
mean, if I need to be online to access the messages, what is the use of
index files? 

If somebody could share an example of configuration or procedure I would
very much appreciate that.

Thanks.

-- 
Garjola.