For the Yak's Legacy DNS Needs:

Network Solutions calls this page "Manage Name Servers".

The URL is undocumented & unlinked but here it is:

https://www.networksolutions.com/manage-it/manage-nameservers.jsp

First log in & use the [Manage Account] button.
Then EDIT YOUR URL to the above.

(If you don't know what Host Records or Glue Records are, you don't need it.)