You will often need to download a "Hybrid Firmware" (HFW) which looks like official Sony software but includes the necessary vulnerabilities to allow the jailbreak. Key Benefits of a Jailbroken PS3
Jailbreaking usually involves formatting the hard drive. Ensure you copy your save files to a USB drive or the cloud (if you have PS Plus) before starting. However, once jailbroken, you can use homebrew to backup saves more easily. Ps3 Jailbreak Download
The drive should be formatted to FAT32, as the PS3 cannot read other formats like NTFS or exFAT for system updates. You will often need to download a "Hybrid
Assuming you have a compatible console (likely a Phat or early Slim on firmware 3.55 or lower), you can proceed with the download. Here is the preparation checklist: Ps3 Jailbreak Download