How to Play Ps2 Games on My Ps3?

My ps3 says it has 232 GB total, so not exactly sure which model it is. It's not the slim, but it's the newer ps3. I got it a couple years ago. I've read that a lot of the newer ps3's CAN play ps2 games. So I downloaded the "PS2 System Data" Add-On from Playstation Store. I also looked up what games would be compatible. So for example, I put Socom 3 US Navy Seals in there, and it still didn't work. I re-read the summary in playstation store where the add-on was at, and it said that you can also install a playstation format disc. Can anyone tell me what it means by that? And more importantly, how I can get this to work out? The games used to belong to me, but after I got my ps3, we gave the ps2 to my brother, who just recently got an xbox, and we won't make a whole lot of money off these games, or the ps2, so might as well keep em right?

only Fat PS3s with 4USB ports can play PS2 games, if u have/get 1 then u will need to download the PS2 System Data from PSN.