The APK is all you need. It carries camd and the kernel module for every KMI and picks the right one when it patches your boot image.

Once installed, the app tells you about new releases (it checks every 12 hours); no need to come back here.
Only needed for "Use local LKM file" during install. Find your KMI with uname -r: 5.15.x-android13-... means android13-5.15.
camd for your computer (patch a boot image without the phone) and caminit. Most people never need them.