I have a newer home that had two existing light sources in the kitchen. The control switch for the light above the sink is located in the kitchen and the light switch for the light located in the middle of the kitchen is on the wall entering into the kitchen. I tried replacing the light above the sink with a pendant lighting. When taking the existing light down I saw that all the wires were black not labeled so I went to the hardware store and bought a circuit tester. I found out that two wires were hot and the other wire did not set off the circuit tester. Previously one of the hot wires was connected to the wire that did not set the circuit tester off, and the other hot wire was by itself. When I hooked up the pendant light I connected all the hot wires and left the wire that caused no reaction by itself, then connected the ground wire to the screw in the mounting bracket. The pendant light turns on, but the other light will not as a matter of fact both light switches turn on and off the pendent light. Am I suppose to separate the hot wires if so how do i know which one to hook up to the pendant hot wire.

Am I able to place my 2 pendant lights above the kitchen peninsula anywhere on want on the ceiling? The canopy need to connect to a junction box. Would the electrician screw the canopy onto the ceiling and then wired it to the junction box? Or does he need to find a stud so I am limited to where I want it placed?