How to Play Goblivion in Solo?

About Goblivion, from BoardGameGeek:

-Goblivion- A Robust Tower Defense Deck Building Game based on a castle siege. Solo or Coop, players team up to repel the attack of goblins and trolls. Your survival depends on your peasants training for combat. According to the cards that will be dealt to you, you will have to make heartbreaking choices and implement a long-term strategy or else, the Bosses will eat you raw! In Goblivion, you're always under pressure and every decision count. The game is about planning, strategy and tactical combat. It implies tough decisions, painful sacrifices and a dose of luck! There is 3 difficulty level for each of the 5 roles with unique skills. You have more than 7 different boss to fight at the end of each game. The co-op mode is active, players play simultaneously! All in all, it's 108 cards, 77 different ones. 2 boards, 32 tokens, 1 wood token, 2 rule books. Save the Goblivion kingdom!