Complex sentence: But when Steph discovers their relationship, she informs Maxine not to socialise with him as she thinks that Earl is definitely a bad influence to her, however Maxine disobeys her rules and started to sneak out to see Earl.
Split into simpler sentences: But when Steph discovers their relationship, she informed Maxine not to socialise with him as she thought that Earl was a bad influence to her. However Maxine disobeys her rules and started to sneak out to see Earl.