Plexus - OBJ Object Tutorial
Starting Plexus 3, OBJ Import is handled through AE's own file importer.
Direct Link: https://vimeo.com/175064063
This older tutorial from Plexus 2 is still relevant for all the other features (except for the OBJ import workflow).
Direct Link: https://vimeo.com/49138935
Plexus OBJ Object Tutorial.