Do the activity Electric
Circuits #1 "Building series and parallel circuits" in the
manual.
When you find a circuit that does something unexpected, first
check that the circuit is connected the way you intended; if you
still don't understand its behavior, make a diagram of it. Tell us
if you find something interesting.
Where have you encountered series and parallel circuits before?
(Don't forget to include things like switches).
Do the activity Electric
Circuits #1 "Building series and parallel circuits" in the
manual.