5. Add the items that you want to trade. Use the Your inventory and Their inventory tabs to add items to the trade offer. Make sure to select what you want from your friend's inventory. 1  If you can't see any items in your friend's inventory, they do not have any tradeable items available.ou can find lots of Groups dedicated to trading, whether it's all Steam items or specific to Team Fortress 2. 1  Hover over your username and select Groups. 2  Click the Browse groups button and type your search terms. 3  Browse through the related groups and join any public groups that seem interesting.