To set the META tags available within the page object, you need to assign to the system collection (added in the production build). Then assign to the page meta object you desire. For example - if you want to set the page description you simply assign it like this:
Collection: <System>
Name: Page.Meta.Description
Value: This is the description.
The following meta tags are directly supported by this feature:
Page.Meta.Description
Page.Meta.Keywords
Page.Meta.Author
Page.Meta.Copyright
Page.Meta.Generator
If you don't see the attribute you need to assign, you can simply place it after the Meta node, it can be dynamically assigned:
Page.Meta.MyCustomMetaTag
Currently no other System objects can be manipulated through the system collection in this way, however this will be extended in future releases.