EDIT: I thought you meant for Android. I'm not sure if the in-app bulk-downloads work on Windows. If it doesn't, you might look at the section of my post below the five hyphens for an alternative.
There is a way to bulk download from the app (per standard work, anyway).
Here's how to do it for The Old Testament:
Gospel Library app->Scriptures->Old Testament->Menu (the three dots)->Download Audio->Download.
Here's how to do it for The New Testament:
Gospel Library app->Scriptures->New Testament->Menu (the three dots)->Download Audio->Download.
Here's how to do it for The Book of Mormon:
Gospel Library app->Scriptures->Book of Mormon->Menu (the three dots)->Download Audio->Download.
Here's how to do it for The Doctrine and Covenants:
Gospel Library app->Scriptures->Doctrine and Covenants->Menu (the three dots)->Download Audio->Download.
Here's how to do it for The Pearl of Great Price:
Gospel Library app->Scriptures->Pearl of Great Price->Menu (the three dots)->Download Audio->Download.
You can bulk download audio for lots of other stuff in The Gospel Library.
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If you want to stream or download the MP3s outside of the app, too, there are ways to do that already mentioned on this forum. Here's a thread that I made that is insightful:
https://tech.churchofjesuschrist.org/fo ... hp?t=40951
In summary, you would need to download this file:
https://tech.churchofjesuschrist.org/fo ... hp?id=4955
Unzip it, and then use `
wget -i` on the playlists (from the command-line) to download them. To stream them instead of downloading them just open the playlists in a media player (such as mpv).
Note that wget wasn't made by The Church of Jesus Christ of Latter-day Saints.