Are you on 3.55 OFW?
If not, you need to downgrade using e3 flasher or progskeet. You need to research that on your own.
Look up your PS3 model to see if it's able to downgrade.
But, to jailbreak just install a current 4.46 CFW on top of 3.55 OFW. Pretty much it. You should have Install Packages under Game.
Check out Rogero or Rebug 4.46 CFW. There are the most use and dependable CFW
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I hope this helps you =)