The answer to 'how to fix faucet installation' is to first turn off the water supply to the faucet, then disassemble the faucet, clean the components, and reassemble it according to the manufacturer's instructions. This may involve removing the faucet handle, stem, and cartridge, and ensuring all connections are tight and properly sealed.
If the faucet is leaking or not functioning properly, the issue may be with worn washers, O-rings, or other internal components. In this case, you may need to replace the faucet cartridge or other parts to restore proper operation. Always consult the manufacturer's instructions and use the appropriate tools and parts for your specific faucet model.