WordPress.org

Upload the plugin directory to your "plugins", or "mu-plugins", directory.

Activate the plugin, if you've installed it in the "mu-plugins" it's not necessary.

Now go to Settings->Menéame Comments to WP and click "Menéame Comments First Load". This will download all the comments of every post sent to meneame and it will activate a system to check for new comments in meneame for posts sent less than 7 days ago.

This system works automatically, so there is no need to intervene.