An ESC has three wires that must be connected to the motor, two wires for the battery and a servo wire that goes all the way to the flight controller. Unfortunately, almost all of the ESCs come with no connectors. So, it is up to you to do all the work and build up the connections.

As you can see in the following image, the three wires and the connectors have been covered with heat shrink. The reason we are using a heat shrink is to protect the exposed metal of the connector from electrical shorts:

On the other side of the ESC, the black and red wire must be connected to the battery through the power distribution board. Again, this step is optional and we can solder the two wires directly to the power distribution board, but if we need to modify anything or change our frame later, we will have to remove these connections and heat the solder to disconnect the wires.

The following image depicts the ESC after soldering a T male connector. Note that a female T connector should already be soldered...