Switch the electric sump pump on and off and check the electrical connections and the circuit breaker to verify the pump is not working. There's no reason to break a sweat with a manual pump if the electric pump's circuit breaker simply needs to be reset. If the unit is not working, continue with the manual pumping.
Lift and remove the corrugated drain cover over the sump pit hole.
Set a 5-gallon bucket next to the sump pit hole and insert the drain hose on a manual pump into the bucket.
Insert the end of the manual pump into the sump pit hole.
Raise and lower the handle on the manual pump to pump out and drain the sump pit's contents into the bucket. Once the bucket fills up, stop pumping and empty out the bucket. Repeat until the pump no longer draws water from the pit or the water level in the pit falls to a safe level as indicated on the markings around the pit hole.