I filled in the meta tags but my site is not ranking in Google, why?

Filling in your meta tags (description and title) as well as the "alt" attributes of your images is one of the first things to do for SEO.

But it is not the only thing!

There are hundreds of actions that can (and should) be implemented to improve your site's search engine optimization.

I invite you to read these articles (in order) which will help you better understand how to optimize your site for search engines: