Go to the link for the bundle. You can search for games in the list. Search for "lullaby". Download the APK, and then install it to your Quest with Sidequest.
Yup, just download the APK file on Itch, connect your Quest to your computer, open up Sidequest, and drag the APK file into the top left corner area of Sidequest to install.
The itch.io purchase also comes with a Steam key if you want to install it that way instead of using Sidequest (see other reply or the Oculus Quest section of the description section for instructions for installing on Sidequest).
