It’s like a half frame on the door with greenery
You mean a garland?
I remember the project you mentioned. They cut a square wreath form in half to decorate the upper corners of the front door, didn't they? I didn't save it, but maybe someone else did?
Is this what you are looking for? http://celebrateanddecorate.com/fall-decorating-idea-diy/
Something like this: https://www.hometalk.com/39347849/make-this-for-your-fall-front-door?