Trade happens after Production. It is a skippable phase. However, it is only seen if there are at least three players in the game. If there are only two players, then the game will continue on with the Shipment phase. Each player in the game has a chance to propose a trade to another player. If it is a computer player's turn, it will decide what to propose, if anything.
Deciding Who To Trade With
When it is your turn, you will see a list of resources in your stockpile on the left side, and a list of someone else's stockpile on the right side. You may choose to view anybody's stockpile by doing one of two things: Choosing that player's name in the pull-down box, or by clicking the player's name in the turn list in the bottom left-hand corner. To choose a player to trade with, choose the player's name and click "Propose a Trade With...". If you do not wish to make a trade, click "Finish Trading" to end your turn.
Deciding On Resources
Once you have chosen who to propose a trade with, you may decide on trade amounts. The boxes with your color indicate your present stockpile levels. The black boxes represent how much you are willing to trade away. Use the pulldown menus to decide how much you would trade away, and click "Ok". Now, similarly, you decide how much the other player would give to you, and click "Ok" again. Remember that you cannot trade away more than you have. You cannot propose a trade that has already been rejected in the same year. If you choose to trade with horses (), the giver must decide from where to remove a horse, and the receiver must decide where to place a horse. You cannot make a trade in which one player would be forced to place a horse on a territory which already has a horse, destroying a horse in the process.
The Other Player Decides
Once the trade amounts have been set, the trade goes to the other player for approval. The other player has the choice of accepting your terms, or rejecting them. If you decide to trade with a computer player, then the computer player will automatically make its decision.
As of version 2001, you can also click "Reject All From Player" to prevent a player from attempting to trade with you for the rest of the year.
Questions? E-mail me at gettmanr.AT.yahoo.DOT.com.