New wiring harness questions

[Nutsac]

Hoping some of the more seasoned vets can help me with my questions. I bought an aftermarket harness that was toted as universal. When I went to start connecting it, I had noticed that a lot of my parts didn't have anywhere to connect to the harness. Let me clarify...the new harness doesn't have a lot of connection points like the stock harness. So...

Am I required to add wires to the new harness to connect things like my horn, turn signals, headlights...

Do I need to purchase another harness?

Are universal wiring harnesses not really universal?

Any help and insights would be greatly appreciated.