1. Go to add new plugin area in WordPress.
2. Upload and install the zip file of Reviewmonial plugin.
3. Create two pages in WP:
a. Title page 1 Form or any name you like and write [reviewmonial] as a shortcode.
b. Title page 2 Reviews or any name you like and write [review_testimonial] as a shortcode.
4. Click on setting option in Reviewmonial plugin and add your FB details like Facebook App ID, Facebook App Secret etc.