Yoast snippet preview not matching actual Google search result

Hi all,

I am very new to SEO so apologies if this is a very obvious question.

I have installed the Yoast plugin and i am editing the snippet preview on the individual pages of my website. I edit the meta descriptions and page title then save the changes. But when i actually search for my website on Google the meta description is not the same as what i put in the Yoast snippet preview box.

Do i have to change it somewhere else too?

Also in my snippet preview box, i can’t edit the URL, it just says “example-post” after whenever i try and change it.

Any help would be much appreciated!