I started my vermicomposting a few years ago by having my grand daughter help me pick up worms from the sidewalk and driveway after a good rain.
We put them in a compost pile and have added food scraps. I have done nothing else with them, (well, I have taken a few fishing from time to time
I have several gallons of casting waiting for me come this spring. And I know the worms winter well because they are all local yocals.