Where can I have my car professionally wired?

Hey guys, I’m not a car person and don’t really know much about cars and it’s mechanisms. I recently tried to set up rear bumper reflector lights for my hatchback and got it to work. Only the left side worked, while the right side was faulty. The only problem I had was that all the safety features popped up on my dashboard and the “BRAKE SYSTEM” light popped up. I also heard a clicking noise by my shift gear, and when I put my hand on it, I could feel the clicking. I removed the rear bumper reflector lights and it’s wiring. I put my car on reverse and the lights on the dashboard went away. Does anyone know how this happened, and where I can get this professionally done?