The terminals of the 3.5mm plug will be wired directly to the corresponding terminals of the quarter-inch 'stereo' plug, but you are going to plug it into a balanced input which is only interested in the difference between signals presented on its hot (tip) and cold (ring) contacts. A balanced input is a differential input -- it only 'hears' the difference between the two signal wires, and completely ignores anything the same!
Mackie has the same port for balanced and unbalanced source or cable. So in case if I buy mackie, is it fine to use my cable (Ugreen 3.5mm to 6.5mm Stereo Audio Cable)?