He takes off part of the outer attachment and you can see the two wires where he is going to attach the lasers.  He then solders the laser assembly to the 6 volt wires.  And, the home inventor here attaches a small red laser site dot.  Always wear protective equipment and don’t try this at home without a professional.  Always wear GOGGLES this is serious stuff no joke!

Btw the actual laser they use in this video is a 2W blue laser that is definitely a force to be reckoned with.  The remote control can rotate and position the red dot for accuracy.  He takes out some balloons and there were some unidentified substances that he took out as well.  Anyways always be safe and enjoy the video.

Just a note I don’t think such a robot would be battle bot compliant if you wanted to enter it in a show.  The lasers would probably be against the rules as would any robots with projectiles of any type.