the new content is all in the island town to the south. Talk to the dragon outside off the clothing store and give him an emerald to unlock it.
I copied my old saves over to the new version but when I load one of my saves right before the ending (castle is fully built), there is no dragon outside the clothing store. Are there other criteria that need to be met? I know it's a short game but I don't really want to invest the next couple of hours grinding away again just to see the new stuff.
EDIT: I should clarify that I know full saves have been shared and I know they probably include the new content, but I want to be able to play through the new stuff myself rather than just look at the CG's.
EDIT 2: Nevermind, I figured it out. Apparently in this save I never did the artist subquest. In case anyone else is having trouble finding the new stuff, don't be like me.
To find where the new content begins, make sure you've finished the sidequest related to a certain struggling artist and find him in your castle!