But these rights {, enjoyed by the women of today,} were secured {through the valiant effort {of many fighters for women's freedom}} and {{first of all} by the great Susan B Anthony}.
secured through the valiant effort ≈ secured by the valiant effort
⟶ these rights were secured <by A> and <by B>.
⟶ <The valiant effort of many fighters> and <{first of all} the great Susan B. Anthony> secured these rights.
I hope this helps!