Thank you for your help!
So it seems from what I can gather, even though our domain is the same, the pages are changing
Example:
to
We need to keep all of the old pages of the website existent on the server and redirect them from the code.
Is this the case? What if we don't have access to the old website code in order to keep the pages?
We dont have a .htaccess file.
I cannot find in our IIS Manager where to access each file specifically to create the redirects. I did find however, a section called "HTTP Response Headers", but it only allows me an entry of a "Name" and a "Value".