Here you can find the links to study the music using the platform SoundSlice. With this platform, you can choose to study the music by listening to YouTube recordings while reading the music, or to choose only your part by selecting "Synthetic" on the Recording Tab. If you choose the latter, you can then click on the Volume Tab to choose whether you want to hear all parts or only your parts (or volume down the other parts so your part will sound dominant), and to change the midi sound (for me it's nicer to study with the sound of "Choir Oohs" or "Choir Aahs" instead of the default piano sound - mostly for sustained long notes).
On the Settings Tab you can change the appearance of the score, whether you want to see all the parts or only your part. If you want to see only your part, just click the "Solo" button on the Instrument Appearance section. You can also play around with the layout to find which one suits you best. I'd recommend "Horizontal" for the layout.
The BPM tab (if you're using Synthetic audio mode) or the Speed tab (if you're using the Video mode for the audio) is for changing the tempo. If you want to just use the given tempo then you don't need to do anything. But if you want a slower tempo to help you study easier, you can change the BPM into a lower value (there's a minus and plus button for the tempo).
* because the notation of Pater Noster is not conventional, I would suggest that you don't start learning with SoundSlice with this song (you need to get used with the platform first) - choose another song first.