The title. I jumped into this without learning about seeding. How do I do it exactly? I'm using JS Torrent on a chromebook but I don't know if I'm actually seeding. Last thing I want to do is break the rules. Any help is appreciated.

You can check your profile here to see how much you've uploaded and downloaded, ratio, the number of torrents you are seeding and leeching, etc.  Just click on the "Profile" link in the blue ribbon at the top of the page.