Downloading a torrent file can be done using a torrent client. There are several torrent clients available, and the best one for you will depend on your specific needs. Here are the general steps you need to follow to download a torrent file:

1. Choose and Install a Torrent Client: Some of the most popular are uTorrent, BitTorrent, and qBittorrent. Make sure to download these from their official websites to avoid any third-party software.

2. Find a Torrent File to Download: Websites like The Pirate Bay, 1337x, and RARBG are popular, but please note that the legality of downloading files from these websites can vary depending on the copyright status of the content and the laws in your country.

3. Download the Torrent File or Magnet Link: Once you find a file you want to download, you can download the .torrent file or click on the magnet link. The magnet link will open directly in your torrent client.

4. Open the Torrent File with Your Torrent Client: If you downloaded a .torrent file, you would need to open it with your torrent client. If you used a magnet link, this step would be taken care of for you.

5. Start the Download: Your torrent client will start connecting to other users who have the file you want to download (called "seeds"). Once it connects to enough seeds, the download will begin.

Remember, while torrenting itself is legal, downloading copyrighted material is not. Always make sure the content you're downloading is free of copyright or that you have the rights to download it. Please note that this is a general guide and the exact steps may vary depending on the torrent client you use and the website you use to find torrent files.

There are several popular torrent sites available, each with its own strengths and weaknesses. Please remember, however, that while using torrents is legal, downloading copyrighted material is not. Always make sure the content you're downloading is free of copyright or that you have the rights to download it. Here are some of the most popular torrent sites:

1. The Pirate Bay: Often abbreviated as TPB, The Pirate Bay is one of the most popular torrent sites. It has a wide range of content and is known for its resilience against legal challenges and shutdowns.

2. 1337x: This site has a clean, easy-to-use interface and a wide range of torrents. It's particularly popular for movies and TV shows.

3. RARBG: RARBG is known for its high-quality torrents and ease of use. It's very popular for movies and TV shows.

4. YTS: This site is the unofficial successor to the defunct YTS or YIFY group. It's particularly popular for movies, especially high-quality releases in a small file size.

5. Torrentz2: This is a meta-search engine that combines results from several search engines to provide a comprehensive list of results.

6. EZTV: This is a popular site for TV show torrents.

Again, please ensure that you are complying with all local laws and regulations when using these sites, as downloading copyrighted material can have serious legal consequences.