How to use to seed torrents

introduction: I’m a beginner
Hi everyone, I’m here writing because I simply can’t share my first file via bittorrent: I can’t seed to the peer. This is probably due to my internet connection. So I decided to try this free service available here
although I believe it is made to run on Linux machines, I managed to run it successfully on Windows. Now, not being an expert in NAT, I don’t understand why I still can’t share my file on torrent.

the port I indicated in the command

curl > tunnel.conf

is still closed. Shouldn’t it be open after the tunnel?