Making new referenced library for Lightroom

My photos are already sorted into this structure, in Aperture, as a managed library:

PHOTOGRAPHY (main folder)

- PROCESSED

GROUP A

GROUP B

GROUP C

PROJECTS

PROJECT 1

PROJECT 2

PROJECT 3

- WORK IN PROGRESS

GROUP D

GROUP E

GROUP F

I want to make the import to Lightroom as smooth as possible, keeping my current folder hierarchy as close to what it is now. Without a lot of reshuffling and potential headaches, which I've read a lot about others having-- while searching around.

How can I make this into a referenced library? What are the appropriate sequence of settings to use (based on my current structure shown above), when I get to the "edit" panel of the Relocate Originals function in Aperture?

Totally confused. And scared to muck it all up before even starting up my new LR journey.