WordPress.org

Where do I insert a map into my post/page?

When writing a post or page, there will be a meta box titled "Yandex Maps for WordPress" just below the "Tags" and "Categories" metaboxes.

Where can I get a Yandex Maps API Key?

http://api.yandex.ru/maps/form.xml

What unit do you expect the map width and height to be in?

If you don't specify a unit, pixels will be used. However, if you would like, you can specify any valid CSS unit (em, %, etc).