The Inventory can be accessed in-game by pressing the 'i' key.
Inside the inventory, you will see ammunition, materials, equipment and Chipsets you have crafted/collected during this deployment.
In this window, you can drop items into a loot container in-planet if you need to clear some space in your inventory, and you can also split items in the inventory into stacks by pressing 'Shift' and dragging items to the in-planet container or organizing or share items with your squad.
You can also see your current installed chipsets in the inventory window.
Note: materials used for crafting will not be shown in Inventory.