Replacement of hotend
Those Pins, are actually Bootlace Ferrules, intended to make a better quality connection, than bare twisted wires.
I would unplug the Heatbed existing connector from the einsy and
loosen the two screws with a flat blade screw driver, remove the old cables and insert the new cables, then tighten with the flat blade screw driver
p.s. the heatbed reference relates to the Mk2 heatbed on the older printer (Rambo mini controller)