The events are described as:
E1 = toss first coin (2 outcomes, so n(E1) = 2.)
E2 = toss second coin (2 outcomes, so n(E2) = 2.)
They are independent, since neither toss affects the outcome of the other toss.
So n(E) = n(E1) × n(E2) = 2 × 2 = 4
[We could list the outcomes: HH HT TH TT].