How are "jumpers" used?
(That looks like an AVR programmer)

The jumper is a tiny plug that connects two pins.



You put the jumper either on the left two pins or on the right two pins. The middle pin is a common pin.



In your case the jumpers are being used as a SPDT switch that can't be accidentally moved.

To change the selection, pull off the jumper and push it into the alternate position.

This applies to each group of three pins