PLEASE MAKE SURE THE DUMPS YOU GET FROM THE E3 ARE GOOD DUMPS OR YOU WILL BRICK.
Anyway After it's on 3.55 you download any 3.55 CFW for example KMEAW or Rogero 3.55 and then install them by either doing recovery mode or just by going to system update, once you have done this you will be on 3.55 and you will notice install package files, you should be able to install pkgs but you won't be able to use them. To fix this, find a jailbreak, such as a CEX, REX or DEX, personally CEX is the best for beginners but if you want to learn to use DEX, be my guest. REX however are pretty much them both together. I recommend Rogero CEX or REBUG CEX. For DEX use REBUG DEX or PS3ita and finally for REX, I think there's a REBUG REX. So now once you have found a jailbreak, install it the same way you did with the CFW. Once this is done CONGRATULATIONS! You are now jailbroken, probably not on 4.75 so DONT UPDATE TO THE LATEST UPDATE, EVER! you will need to find a spoofer, perhaps youtube.
Homebrew/Third Party Applications:
To install these, you will need to find some on youtube or google and download any application you desire. Once you have this put them on your desktop and then extract them if they're a rar or a zip and then you should have the file as a pkg, so now put it in the root of your usb and head to your ps3.
Go over to install package files on your ps3 then it should be there or there could be multiple options, keep following the options until you use the same packag. As you saw on your PC and then click it and then it should restart your ps3.
Recommended Homebrew:
Multiman
REBUG toolbox
FTP blackbox
Enstones Console Control (MUST HAVE IF YOUR MOD GAMES, PLUS NEEDED ON BOTH PS3 AND PC)
FileZilla (PC application)
SEN Enabler (Spoofer)