Complex sentence: Steve tried to trick his father into signing his report card by claiming his teacher wanted Stan's autograph, but Stan doesn't fall for it (after Hayley points it out) and learns that Steve is flunking the creative writing class.
Split into simpler sentences: Steve tried to trick his father into signing his report card by claiming his teacher wanted Stan's autograph. But Stan doesn't fall for it and learns that Steve is flunking the creative writing class.