Follow these steps:
1. Open the cartridge access door on your HP Photosmart c4480.
2. Wait for the print carriage to move to the center.
3. Press down lightly on the ink cartridge that needs to be replaced to release it.
4. Pull the old cartridge out towards you.
5. Remove the new ink cartridge from its packaging and remove the protective tape.
6. Insert the new cartridge into the appropriate slot, making sure it is firmly in place.
7. Close the cartridge access door.
8. Follow any on-screen prompts to align the cartridges if necessary.
That's it! You have successfully changed the ink in your HP Photosmart c4480.