WordPress.org

1. Download the plugin
2. Unzip momentile-on-wordpress.zip
3. Upload the entire momentile-on-wordpress folder to your plugins directory
4. Go to the Plugins page in your WordPress Administration area and click to 'Activate' Momentile on WordPress.
5. Add your Momentile username on the settings page, and change any other settings as required

Then either:

1. Go to Appearance->widgets and add the Momentile on WordPress widget to your sidebar

or:

1. Open your theme folder
2. Open sidebar.php in a text editor
3. Add into the code where you want the widget to be