in the CMD window, type ipconfig and note the IP address
Most likely something like 192.168.x.y
On your Samsung TV, enter the address as above for Development
Same YouTube video, about 2:52 minutes in
Then select Application Sync
Doing above, should install a new Plex App on your TV, and if so, launch it and wait until it ask for a proxy server, and then enter the same IP found earlier
If above does NOT happen, then you most likely didn’t stop your Windows firewall!