Custom Folders and what goes into them

I have printed off the sheet which shows me where I should put my CUSTOM folders.
I know that any changes which need to be saved (most of them I suppose) need to be copied into the CUSTOM folders.

My question is, do I put ONLY the files I've changed into the CUSTOM folders, or do I put everything from the original folder in there as well as the changed one/s?

I know this is a totally newbie question, but I didn't do it last time around because I couldn't understand it.

Thanks
Jenvin

You only put the files you changed in them. Zen cart will then automatically recognize it as an override

Design75:

You only put the files you changed in them. Zen cart will then automatically recognize it as an override

Thank you design75, thank you so much. :)
Love your big cat. :)