macos – Installing Tiger on an iBook G4 A1134 running Leopard

I have recently acquired an iBook G4 to run a specific software for research. The iBook currently has Leopard installed but the software I want to run doesn’t work since the iBook doesn’t have the classic environment. Because of this, I’m trying to downgrade to Tiger or Panther but I don’t have installation disks. I have been trying to follow the USB stick methods but these aren’t working. The iBook doesn’t show the USB when you boot holding the option key. I’m not sure if this means there is some problem with the disk image I’m using. I have tried .dmg and .iso. Is there some recommended place to download the disk images? Is it even possible to install these older systems using this method?