Build a 7th level character by the book.
Generate stats by rolling 4d6 dropping the lowest die.
Choose Race and Class at will.
In addition to your starting equipment roll 4d4x10 for extra starting gold. Your corporate job has paid well.
Everything else build by the book.
Remember to roll for Trinket.
Post your Race, Class, Name, Flaw, Bond, Passive Perception, and Trinket before Thursday.
Do not worry about optimization that is not the focus of this adventure. The module describes itself as being for “Woefully Unprepared 7th Level Characters” When in doubt choose what would be most fun thematically to character you want to play.