I think you're confusing the .torrent files with the actual torrent's contents. In order to open the .torrent files on an Android device, I would recommend first going to the Google Play store and downloading uTorrent for Android. In order to properly seed torrents from your android device, you may need some special provisions programmed into the wireless router your phone is connected to, otherwise, it would be your mobile data carrier you would need to consult if your android is not directly connected to the internet when using mobile data.
I would however caution against the use of uTorrent for Android while on mobile data, at least until you verify what your mobile data rates are with your carrier. Within North America, mobile (cellular) data is rather expensive and seeding or downloading torrents is rather data intensive, especially if you're downloading entire DVD images. Once you have downloaded and installed uTorrent for Android, you should be all set to open the .torrent files to be able to start downloading their contents. I would caution you as a new user though that your ratio is important, so starting off with the correct selection of torrents is critical to ensuring that you start out on the right foot. As a general rule, downloading of freeleech torrents is a good way in which to download without having to worry about it affecting your ratio. Aside from that, I would recommend that you read our Suggestions for Newbies thread as well as our Guide for Starters in the forum. You may find these useful in helping you to get off on the right foot.