Thanks Breezer,
Just creating a TV seemed to be the easiest.
here’s what I did.
Typed the following code into my template:
<meta name="description" content="[*description*]" />
Or whatever other tag I want "author" etc.
Created TVs called "description" "author" etc
That’s it, it works, problem solved, the fields are now where I expect them to be on my individual documents, and I can enter whatever I want.
No need to download anything.
Although I’m still at a loss as to what the actual manage meta tags function in Modx actually does.