I want to ask about custom field template plugins

I found custom field template plugin for my custom field solutions - I used it with custompress.
Both make me solve many projects.
That's a long time I can find any support or discussion about custom field template.
I really want to find document about it,
Example : get all group field and show them into an order list.
I want to know structure of custom field template (CFT) so that I can solve my solution myself.
Who can help me? Thanks a lot!