You have to plug it into your PC for starters. You may require an additional cable as my one was different connections.
You say you got it off a friend, so i guess if it allready came from a PS3 it should allready be formatted to FAT32.
If you are unsure and cannot connect to your PC, take it to a computer store and have them format it for you.
It will have to be partitioned as FAT32 is only for 32gig.
I could have bought the cable to do this myself but instead got the PC shop to do it for me.
Once formatted to FAT32 you can transfer your gamesaves and system data to your portable drive, and the PS3 will recognise the files.