What sort of help do you need thought? All I am saying is that you cannot just put in any site into “redirect from” and get all the traffic from it, that would be weird.
To use redirect from one domain to another you need to point both to your webflow project. This will make old site gone though. If you want to keep old site online you will need to set up redirects somewhere on the hosting panel of your old site. but that would be pointless - if you are not using your old site by redirecting everything to your new webflow site then there is no need to keep it and it is safe to connect that old domain to your project anyway.