Just download a cfw and you're good. If you want DEX and online look in the PS3 cheats and customization you'll find tuts.

Tbh cex is much easier , i converted to dex today and its stressful and but much better in the rtm tools , get 4.46 rebug you can change from dex to cex in 5 sec thats what they are saying i haven tryed it , i was on rogero 4.55 and it was like a little pain in the ass because if your trying to go to dex you need to downgrade and shit its a pain , ask other that have more time in dex

Put on 3.55.4 rebug. Go in rebug toolbox and look for QA Flagging and turn it on. Restart the console then get 4.46.1 rex cfw from rebug
Put it on a usb and update to that now. After you are on 4.46.1 rebug you'll want to find a spoofer. You can try this but not sure if it's for only dex You must login or register to view this content.

It's simple. Just download your CFW and install it. Once you do that, find a valid spoofer for your corresponding firmware. Once you do that, you are ready to go on PSN and play.

splat some rice and mustard inside your ps3, go to the xmb menu then system restart and boom! your ps3 will be on a cfw firmware