Marketo Account Structure

I realize this may be a basic question for some, but is there a guide or document that provides an overview of the structure of the Marketo account? I'm unsure of the relationship between folders, programs, campaigns, etc. within Marketo. I have a marketing campaign that I would like to setup within Marketo, but the terminology is throwing me off a bit. I would appreciate any help or pointing toward resources that anyone can offer.