what is the easiest way to make a worm bed?

Image by drmacro
Worm bins. Newly-started bin on left, having had worms migrate into it from old bin on right.

Question by Zac: what is the easiest way to make a worm bed?
how would i start a worm bed and how to get the worms from like the store and jus let them populate
and why dont i wont night crawlers they are the bigger ones and red worms are small right
i want to have night crawlers for fishing bate to sale

Feel free to answer in the comment section below