I changed my domain name to a transfer, what do I do about all the dead links now?

I changed my domain names around, and now Google has a bunch of links that are dead, that I want pointing to my site. Since the old domain is now a redirect, how do I take advantage of all its search engine links? I dont know how to apply a custom 404 page to a redirect and am not sure how to add a server side include to help me. I am not formally trained but somewhat knowledgeable. Also, my worrie is not the top level of the domain, but it's sub directories. You can see what I'm talking about if u google treasure titan Thanks.
I changed my domain name to a transfer, what do I do about all the dead links now?
The only way:

- Keep the original domain website active.

- Replace every page that is linked with Google with a %26quot;redirect%26quot; page to your new domain.

(say you had a link to mypage.com/subdir/index: index becomes the redirect to %26quot;mynewpage.com/subdir/index%26quot;.)

Could be a lot of work if you have a lot of links, but that's the only way to keep your ranking.