When two or more devices are wired in series, they are arranged such that whatever charge passes through one device will also pass through the other device. There are no branching locations where a wire divides up into two or more possible pathways. Instead there is a single pathway by which a charge can pass from the + to the - terminal of the battery. As the charge makes its way along this one pathway, it first passes through one bulb, then through the second bulb, and finally through the third bulb until it reaches the - terminal fo teh battery and starts the cycle all over again.
Devices wired in parallel are much different. Parallel arrangments of light bulbs allow charge multiple pathways by which it can traverse an entire loop from the + to the - terminal fo the battery. A wire attached to the + terminal will eventually reach a branching location or node, where that one wire divides up into two or more pathways. Each pathway or parallel branch includes a light bulb. During any given loop around the circuit, any charge that passes through the first light bulb will not pass through the other two light bulbs since they are not wired consecutively. So some charge will pass through light bulb 1. Other charge will pass thorugh light bulb 2. And of course the remaining charge passes through light bulb 3. But none of the charge will pass through all three light bulbs during a loop around the circuit.
