[Plugin: Yoast SEO] Adding Keywords and deleting content

Hi,

I can’t seem to add keywords into my site, it seems to not come up with a meta keywords tag at all in the head. I am actually a little worried using Yoast, as my site is based on a theme using page builder, for some reason when ever I edit something on Yoast it deletes all the content on the site.

This is more a “how do I add keywords to my site?” And then if anyone knows why Yoast is deleting my content I would like to know.