I don’t see an out of the box, Archival reference type.
So first you would create that ref type from one of the “unused” reference types (in preferences).
Then you need to create the “template” for the style in APA 6 output style. I usually start by copying the generic to the new template, which changes the fields to the names you gave them in the ref type, deleting extraneous items, and punctuation, and cleaning it up and adding missing fields as necessary. I am trying to add some tools, but i am having trouble getting into the knowledgebase right now.