An excellent browser, such as IDM+, can let you download the media.
Afterwards, you can extract the audio file with an app...
https://f-droid.org/en/packages/protect.videoeditor/
Once that is done, find the file and play it.
Once it is playing, go into the menu of your music player app and select 'set as' to maake it your ringtone.
You can also find it in your file manager and then long press it.
A menu with the same 'set as' option should appear.
Otherwise, go to where you set your ringtones, and select 'music' and then locate the file and select it.
Keep in mind that when set as a ringtone, quite often the entire song will not be played.
If a certain part of the song is what you desire as a ringtone, keep this in mind when you are using the Video Transcoder app.