For watching movies and shows there is nothing simpler than Stremio with the Torrentio addon.
For other files I don’t like the BitTorrent protocol for sharing because it complicates file sharing, requiring files to remain in their original locations without renaming when creating a torrent. I prefer Nicotine+ and Fopnu as they allow me to easily select folders for sharing without any complications. These are the only programs I know of that are compatible with Windows and Linux and are actively developed. They are newbie friendly because searching for files inside the program is straightforward. I’ve also used eMule, Gnutella, DC++, Shareaza, MLDonkey but I don’t recommend them. Although eMule has good availability for old/rare content.