Click a switch to operate it. Click any bulb to unscrew it and put it back.
Goal: wire the run so each switch controls the lamp above it — and nothing else. The four dots inside each octagon are splice points; land as many wires on one as you like, that is your wire nut. Click a terminal, then another, to run a wire.
Click a terminal, then click another terminal to run a wire between them. Click a wire to pull it out. Then flip the switch and see if the lamp lights.
Drag a part from here onto the grid. Drag it again to reposition, or hit its × to remove it. Click terminal to terminal to run a wire, click a wire to pull it out. Nothing is graded — the lamps light only if the wiring really works.