eMac G4 Recovery Mode with Windows Keyboard
OS X Recovery was introduced with OS X Lion. At best, your eMac supports 10.5.8 Leopard. If you want to install from scratch, you'll need either the original install disks or a system installation disk.

You can bring another bootable OS X drive that runs a supported OS for that hardware and get to things like terminal / Disk Utility as well but this hardware pre-dates recovery on the firmware / OS level.