How to fix pins onto a 3-pin PWM cable?

[arrou.keys]

Can someone tell (or show) how to fix pins onto a 3-pin PWM cable? It's the thin cable that's red, black, and white, with a black piece with 3 small pins on the end (used for VEX Robotics).

We have only one side with pins, but need the other side to have pins, as well, but we don't know how to put the pins in.

Do you have to take the end-piece apart, or are you supposed to somehow force the pins in?

Thanks!