301 redirects from old website--Best Approach?

I have a number of urls from my old site that I want to direct to completely new urls… I’m kind lost. Reviewed Routing but… not sure where to put

pages: redirect_default_route: false redirect_default_code: 302 redirect_trailing_slash: true

/jungle: ‘/blog/the-urban-jungle[303]’

Ok. The redirect goes in the site.yaml and I got that working.
/joys/creating-a-household-notebook/everyday/205-its-okay-to-let-go-of-old-greeting-cards-really-it-is: ‘/organize/its-okay-to-let-go-of-old-greeting-cards-really-it-is[301]’

But something curious is going on with the Simple Aliases
when adding this to my site.yaml
/joys/creating-a-household-notebook/everyday/205-its-okay-to-let-go-of-old-greeting-cards-really-it-is: ‘/organize/its-okay-to-let-go-of-old-greeting-cards-really-it-is’

The page displayed but the content was duplicated in the footer…