Activating a C00/Demo package is very easy and doesn't require a rap file. It can be done using ReActPSN or PSNPatch.

ReActPSN : Run the homebrew while pressing and holding circle on your controller.

PSNPatch : Run PSNPatch and press R1. It should displays a list of the games that have been unlocked.

Activating a package using a rap file requires few steps. It can be done with ReActPSN or PSNPatch. However, I will only describe how to do it with ReActPSN.

1. Format a USB key in FAT32.
2. Create the folder 'exdata' at the root of the USB key.
3. Move the corresponding RAP file for the games you want to activate in the exdata folder.
   Warning: Do not rename rap files ! You need to leave their original ugly name.
4. Connect the USB key in the right USB port of the PS3 (the closest to the bluray drive).
5. Delete the ReActPSN user on your PS3 if it exists.
6. Create the account 'aa' (without quotes) and open the account.
7. Run ReActPSN and the screen should go black, then you should hear beeps and then the PS3 should reboot.
8. The user 'aa' should be gone now and the account 'ReActPSN' automatically created.
9. You're done !