A method for operating a gas turbine engine facilitates reducing an amount of emissions from a combustor. The combustor includes a mixer assembly including a pilot mixer, a main mixer, and an annular centerbody extending therebetween. The method comprises injecting at least one of fuel and airflow into the combustor through at least one swirler positioned within the pilot mixer, and injecting fuel into the combustor through at least one swirler positioned within the main mixer, such that the fuel is directed into a combustion chamber downstream from the main mixer.