Stepping Stones - How to Play (Game + All Contracts and Variants Explained)

About Stepping Stones, from BoardGameGeek:

Stepping Stones is a compendium trick taking game that is designed to be a "my first compendium game" for players familiar with trick takers, but unfamiliar with compendium trick takers. So, what is a compendium game and how does it play? It is a game where there are multiple objectives that each player must complete by the end of the game. These objectives are commonly referred to in traditional games as “contracts”. Each player must complete every contract before the game can end. Most importantly, once a player completes a specific contract they cannot attempt to complete that contract again. Contracts will slightly change the rules of play for all players. To determine which contract is played in a given hand, there is a bidding phase where players go around the table picking a contract they want to play or passing. In Stepping Stones, once a player picks a contract the bidding phase is immediately over and that player becomes the "declarer". If all three players pass, the starting player is forced into being the declarer and must pick a contract! The declarer's score is the only score that matters for the hand. The other two players, referred to as "defenders", are trying to stop the declarer from doing well at their contract. Once all players have been the declarer for a specific contract, scores are compared. The player who scored the best in that contract gains game points while the player who scored the worst will lose game points. After all contracts have been played (12 hands), and scores are compared for all of them, the player with the most game points is the winner! —description from the designer