@Reo28 There are a few apps on Android that support Torrent downloads - you want to make sure that you're using a 'local' service (one that runs on the phone) rather than a 'remote' service (which is designed to control a server doing the work elsewhere).
Transmission is a good place to start, as this is a reliable open-source app with no annoying ads or other monetisation.
You could download one from the Play Store like "Transmission BTC" (BTC stands for BitTorrent Client, nothing to do with crypto), set the preferred download folder on your phone to somewhere you can access easily (like Downloads) and use it to open the .torrent file you got from the site. The file will appear in the in-progress area on the app and you can monitor it there. If you want to keep your GT profile in good standing, try to keep it active until you've contributed roughly as much data as you've downloaded.
One thing to bear in mind is that while this will work on your phone, torrenting may continue in the background and may be demanding on your phone in terms of battery life or data usage. If you need to do it on your phone, better to do it while connected to WiFi, for example overnight while on charge.