I will assume that you already have TFS setup and are just using HTTP and want to make things a bit more secure with HTTPS. I am also assuming that you will be using port 443 for HTTPS traffic.
To update TFS to use HTTPS you need to do a couple of things:
Have a legitimate certificate installed on the server that you can bind to
Have an IP address on the server and have firewall access setup to that IP address on port 443
But there are a few more steps as well, so click through to see them all.