First in the relax ending go to the biat and read the note and then he Tells you to find the glowing key which is in the shack and then u fight hım in which u spare hım to get the shard (sigh) in which u hibe to the Man who speaks in hands (gaster) and there u go ITS more like rng and tries than clues but still. (Just realized i had a stroke while writing this)