The desktop app is the whole library: every book, all seven sections, the audio narration and the word-by-word synced reading. Sign in and your progress, collections and notes stay in step with your phone. It needs an internet connection to open — offline downloads are on iPhone, iPad and Android.
Windows Download for Windows Installer for 64-bit Windows 10 and later. It sets itself up and opens when it is done. Linux Download for Linux Package for 64-bit Debian, Ubuntu and the distributions built on them. Open it with your software installer, or install it from the terminal.
About the warning you will see
Neither installer is signed yet. Windows greets an unsigned one with a full-screen security warning the first time: open its details and confirm you want to continue. A signing certificate is on the list; until then this is the honest state of things.