How to add a Like Button using iWeb?

Hello, I want to add a Facebook Like Button to my blog. I use iWeb, and have iWeb SEO Tool but not so sure how to use it. I read on the Facebook website that if you want to change the display site name and title you can add meta tags like "og:title" or "og: site_name". Does anyone know how exactly I can do this on iWeb SEO Tool? I tried many times but it never worked. The display on Facebook is "Alex likes www.xxxxxxxxxxxxxxxxxxxxxxxxxxxx.com" it's a LONG one, I want to change it to my site name.

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Digital Agency
Digital Marketing Agency