The simulation shows a simple circuit, with a battery, a switch, a resistor, and a few wires. Conventional current shows the Ben Franklin view of the circuit, that the flowing charges are positive (shown in red). In actuality, the flowing charges in the circuit outside the battery are negative (shown in blue) - they are electrons - while the ones inside the battery are positive. For the "Actual" situation, note what happens at the two terminals of the battery. This looks a bit like magic, but is actually chemistry.