Some items needed to complete tasks in temporary expeditions can only be created from other items through crafting.

There are certain structures on the locations through which crafting is done. 
When you tap on a structure for crafting, the crafting menu opens.  It displays the items that can be crafted on the right and the recipe for crafting them on the left (the list and number of items needed, as well as how long it will take to craft).
 

Crafting starts when you drag the item you want to craft to the cell at the bottom of the menu. You can only drag an item into the cell if all the resources for its recipe are available.

If there are not enough resources, the item will not move and a pop-up window will appear, offering to buy resources for banknotes.

Besides buying them, you can get the missing resources by collecting them on the location or growing them on the garden beds.

When the item is ready, the item icon will appear above the crafting building.  
When you tap it, the item will be transferred to your Inventory.