If you've removed the https://www.nivito.com plumbing, you can change the faucet yourself. Simply follow the instructions on the packaging. Be sure to tighten all screws and nuts tightly to avoid the risk of leakage. Then, you can replace the old faucet. Before you do that, dispose of all of the old parts. You may also want to remove the plumbing, but this will make the job much more difficult. If you don't have the experience, consider hiring a plumber to do it for you.