Complex sentence: Brennan shows up and they walk to where the corpse is; finding a body in a suit that Booth says they think is BDSM gear, and a bag with degraded cellulose and maggots in it.
Split into simpler sentences: Brennan shows up and they walk to where the corpse is. They find a body in a suit that Booth says they think is BDSM gear, and a bag with degraded cellulose and maggots in it.