Diablo 4's trading system, generally speaking, is a trading system that uses Diablo 4 gold coins as the main currency, equipment and legendary powers as the main carrier, and mixed with various consumables and service content. Although we don't have specific information on Diablo 4's mechanics, I can make an educated guess based on how trading typically works in similar games. Here's a speculative outline of how trading might occur in Diablo 4:

In-game Communication: Use the in-game chat or communication system to reach out to the player you want to trade with. Coordinate a meeting location.

Meetup: Once you've agreed upon a meeting point, gather both players in the same location within the game world.

Trade Interface: Diablo 4 might provide a dedicated trade interface or window where players can conduct their transactions. Open the trade window, which may include separate slots for each player's offered items.

Item Presentation: Drag and drop the items you wish to trade from your inventory into your designated trade slots. The other player will do the same on their side of the trade interface.

Offer and Negotiation: Discuss the value and terms of the trade within the chat or through the trade interface. Make any necessary adjustments or compromises until both parties are satisfied.

Confirmation: Once the trade has been agreed upon, both players can confirm their readiness to finalize the transaction. This step could involve a final review of the items being traded before acceptance.

Trade Completion: After both players have confirmed the trade, the items will be swapped between their respective inventories, completing the transaction.

Remember that this is a speculative answer, and the actual trading mechanics in Diablo 4 may differ when the game is released. Be sure to consult official sources, community forums, or the in-game tutorial to obtain accurate information on trading within Diablo 4.