if this realy the most appropriate place?
given he was going mad and half the film is his delusions if you're stuggling with this i'd realy ask your teacher for help.
nash is schizo. while we're not told how much of the soviet conspiracy is in his mind its definite that some of it is. the whole back shed filled with paper clippings is proof of this. during the movie we dont know that its only is nahs's head but at the end its revealed that it wasall imaginary, thus linking to imaginative journey. also parcher is imaginary as well.
not sure if that'll be much help as its more a general explination of the film but not sure what you focus on in IJ