Assuming everything goes as planned, after a year or so, you should be selling enough CDs at gigs and making enough of a name for yourself that you can start moving some units in record stores in the towns you play in. You've got yourself a distributor, they're stocking the stores. Radio stations begin to hear about you. Now, they'll play your record. It's a hit.
Units begin to fly out of the stores.
But wait, the distributors are out of stock. They need another ten thousands units and they need them quick. I forgot to mention that the distributor hasn't paid you for the units sold yet, because they haven't been paid by the record stores yet. Now you're beginning to realize why businesses have cash flow problems. They have to wait thirty, sixty, maybe even ninety days before they get paid.