I recommend putting the battery adapter back into the tracker terminals and clamp them down tightly with the screws. It’s the easiest way to grab the exposed metal pins without shorting them, which would happen if you grabbed them directly with pliers. The battery has built-in cell protection against shorts, but it’s best to save that safety circuit for backup duty.
Then use pliers to grab the white plastic connector next to the wires.
The two plastic bumps on the battery connector are what latch it together. You can shave those down with a knife for an easier fit, but having a strong latch can be a good thing. More than once (!) I have found my tracker laying by itself in the dirt, with its battery still attached but the rest of the av-bay blown up and torn apart after a failed apogee deployment followed by a high-speed main chute deployment.