Good question! The best way is to have already grown enough bacteria to support the fish. You'd want to start weeks in advance by adding pure ammonia to about 4ppm every morning until is tests 0 later in the day.
Of course, you could just borrow an established filter pad from somebody's pond and shake the muck off in there to jump start it. But you have to feed the bacteria you've added or they will just die. I do this by adding the fish and muck at the same time. That's how I always set up new tanks and it cycles in about two days.
Did you dechlorinate all the water?