WordPress.org

1. Upload tantan-flickr to the /wp-content/plugins/ directory
2. Activate the plugin through the 'Plugins' menu in WordPress
3. Configure the plugin in the 'Options' (or 'Settings') screen by following the onscreen prompts.

If you need more help installing and customizing templates, see here for more information. Feel free to post your question into the support group if you get stuck.