Complex sentence: Jimmy reveals to Lois that LexCorp discovered Kal-El's empty spaceship and found traces of his DNA on it, creating Bizarro clones and grafting the DNA onto various test subjects, turning them into Kryptonians.
Split into simpler sentences: Jimmy reveals to Lois that LexCorp discovered Kal-El's empty spaceship and found traces of his DNA on it. The DNA was then used to create Bizarro clones and to graft onto various test subjects, turning them into Kryptonians.