Chosen Solution

I got this powermac g5 at the garrage sale and the unit did not has a hard drive. I need to to know how install mac os to this hard dirve

Your machine will handle up to 10.5.8. You can call Apple and buy a system restoration disk made for your machine for $15 plus shipping. Or your can buy a 10.5 retail installation on eBay or from someplace like www.fastmac.com. You’ll need to install the drive and use Disk Utilities to format it before installing a system.