1: Get a VPN; plenty to choose from, but it will reduce your risk of legal issues from 'small' to 'completely negligible'. It prevents corporations (including your internet provider) from finding out who you are, and it at least makes it difficult for governments to find out who you are. Using a VPN will keep you safe from lawsuits or prosecution in almost all cases. As long as you're not torrenting child porn or terrorist recruitment videos or something, you should be safe with just a VPN.

2: You need to install a torrent client on your computer. I recommend qbittorrent, but there are lots of other options.

3: Search the Pirate Bay or any other torrent listing sites that have the things you want to download.

4: When you find something you want to download, the site should give you a 'magnet link' or a .torrent file. Either one is fine, some will offer both.

5: When you click a magnet link, it should attempt to open the link in your torrent client. Give it permission to do that if it asks for it. When you download a .torrent file, it will hopefully automatically open your torrent client to download that torrent. If it doesn't automatically start your torrent client, try double clicking the .torrent file or dragging and dropping it into your torrent client's window.

6: (If there are enough people seeding) your torrent will start downloading. It downloads in small chunks, and each chunk can come from a different person who is downloading (leeching) or seeding the torrent. Once you have at least 1 chunk complete, your torrent client should automatically begin offering the parts you have to other downloaders (leechers), even if you haven't finished the entire download yet. (You don't have to download the entire torrent, either. If, say, you're downloading a torrent that's a season of a TV show, but you only want one episode, you can go into the files that torrent is offering and deselect the ones you don't want.)

7: When the download finishes, just don't move or delete the file, and leave your torrent client open. It will automatically make your finished downloads available to others (seeding). As long as you don't move or delete that file, and as long as you don't stop your torrent client, it will continue to seed and provide chunks of it for others to download from you.

8: It's wise to run a virus scan on anything you download before opening it.

If it's going really slow, that's likely because there are more leechers than seeders. Either try a different torrent or just be patient. A lot of leechers will become seeders once their download finishes, so sometimes the ratio improves over time.

If a torrent stalls entirely and is making no further progress, it's likely because there are no seeders, and you've already downloaded everything that the other leechers have. Might have to give up on that one or try a different torrent for the same content. But it's often a good idea to leave that stalled torrent running anyway. Who knows -- sometimes a new seeder comes online weeks or months later and suddenly makes it complete again ... and then once you have it at 100%, you become the seeder who's helping everyone else out who wants that content.

For both of the above issues, take note of the number of seeds and leeches on each of the torrents you're thinking about downloading. Often, you'll have multiple options of which one to download, and the one with the most seeds will usually be the fastest and most reliable. Torrents with less than ~3 seeds can be unreliable and often fail ... but sometimes, it will work if you have even just 1 seed, so if it's something you really want and there are no other options, it's worth a try. But a torrent with 0 seeds is effectively dead -- you can try it and hope that a seeder will come back, but that rarely happens.

Check to see if your internet provider has a monthly cap on uploads and/or downloads. Mine does, and will charge a lot extra if you exceed it. So I mostly only torrent around the end of each month, when I'm using up my remaining data cap before it restarts next month.