look at the books with all the letters showing - "trenchcoat astrologer" - and then arrange the letters in order according to the FIRST message (i.e. the order of the sun and planets in our solar system),
The SUN book has the letters: h
l,
so write hl, and continue on in this fashion to get: hltrcorsethrcoogaeta
We need a six-letter code, and we see that "corset" can be found among the garbage letters (also note that there is a corset on the left side of the main screen with the fireplace...), so type it in and voilà, we finish the episode.