How can I attach a schedule to a flow?

Prefect 2.0

You set a schedule as part of the DeploymentSpec:

from prefect.deployments import DeploymentSpec
from prefect.orion.schemas.schedules import IntervalSchedule
from datetime import timedelta

DeploymentSpec(
    flow_location="/Developer/workflows/my_flow.py",
    name="my-first-deployment",
    parameters={"nums": [1, 2, 3, 4]}, 
    schedule=IntervalSchedule(interval=timedelta(minutes=15)),
)

Prefect 1.0

You attach the schedule to your Flow object:

from prefect import Flow
from prefect.schedules import IntervalSchedule

schedule = IntervalSchedule(interval=timedelta(minutes=15))

with Flow("scheduled_flow", schedule=schedule) as flow:

Additionally, you can test the schedule by printing the next schedules as follows:

from prefect.schedules import IntervalSchedule

schedule = IntervalSchedule(interval=timedelta(minutes=15))

for sched in schedule.next(10):
    print(sched)